I predict the Square Cash App BTC rollout will be detriment…
I predict the Square Cash App BTC rollout will be detrimental to BTC...
When millions of users try to withdraw from the Lightning Network to on-chain BTC my guess there will be severe on-chain congestion and transaction fee spikes.
Square (Block) has launched automatic Bitcoin payments for millions of U.S. merchants, enabling them to accept Bitcoin at checkout with zero processing fees through 2026 and near-instant settlement via the Lightning Network.
Bitcoin Conversions allow eligible sellers to automatically convert 1% to 10% of their daily card sales directly into Bitcoin, which is deposited into their Cash App account daily; this feature includes a 1% conversion fee and is available to U.S. merchants excluding those in New York.
In a major rollout for November 2025, Square began enabling these Bitcoin payment capabilities by default for roughly 4 million merchants worldwide, allowing instant transactions without the need for manual setup or holding Bitcoin volatility.
Cash App Integration: Users can withdraw up to $10,000 daily and $25,000 weekly, making it a primary on-ramp for Bitcoin in the U.S.
Future Goals: Block aims to integrate Bitkey self-custody wallets with Square to allow automatic sweeps of Bitcoin payments to self-custody by 2026.
Revenue Impact: Cash App's Bitcoin revenue surged 1,000% to $1.63 billion in Q3 2020, highlighting the platform's significant financial growth in the sector.
Cash App does not automatically convert Lightning Network Bitcoin holdings back into on-chain Bitcoin. Instead, the conversion happens manually when a user initiates a withdrawal.
Here's how it works:
Lightning for Speed: The Lightning Network is used for fast, low-cost transactions within the Cash App ecosystem and for sending/receiving small amounts.
On-Chain for Withdrawals: When a user chooses to withdraw their Bitcoin to an external self-custody wallet, Cash App executes an on-chain transaction. This process moves the Bitcoin from its internal Lightning/custodial system onto the main Bitcoin blockchain.
User Control: The user triggers this conversion by selecting the "Withdraw Bitcoin" option and providing an external wallet address. The Bitcoin is then sent via the standard blockchain, incurring a network fee.
In essence, the Lightning balance is a fast, internal ledger for spending and receiving, while the on-chain network is used for final settlement and moving funds out of the Cash App platform.
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BTC being stress tested with millions of on-chain transactions could be great news for bigger block Bitcoins.
If BTC with small blocks cannot operate efficiently as a large payment network the small block narrative collapses
Lightning Network withdrawals to the Bitcoin main chain generally cannot be batched. While the Lightning Network itself allows for the batching of multiple transactions within off-chain payment channels to improve efficiency, the process of moving funds back to the on-chain Bitcoin network (often called "looping out" or using a "swap-out") typically treats each withdrawal as a distinct on-chain transaction.
Platform Limitations: Specific platforms like Bitget explicitly state that "The Lightning Network does not support batch withdrawals," requiring each transfer to be processed individually.
Technical Mechanism: Converting off-chain Lightning funds to on-chain BTC usually involves a "reverse submarine swap" or a direct channel closure, both of which result in a single on-chain transaction per batch of funds rather than a consolidated batch of multiple distinct withdrawals.
Exceptions via Services: Some third-party services (e.g., Bitcoin Well) may offer a "batched" transaction option where multiple swap requests are consolidated into one on-chain transaction, but this is a service-level feature rather than a native Lightning Network capability for standard withdrawals.
Unlike standard Lightning transactions which are ephemeral and never recorded on-chain, every withdrawal to the main chain requires a confirmed on-chain transaction, meaning the batching benefits of Lightning do not directly apply to the final settlement step unless facilitated by specific custodial or swap services.
BTC blocks cannot handle millions of separate on-chain transactions daily because the base layer is limited to approximately 3 to 7 transactions per second, which translates to a theoretical maximum of roughly 400,000 to 867,000 transactions per day depending on transaction size.
Block Constraints: Each block is limited to roughly 1 MB of data (or up to 4 MB effective weight after SegWit) and is generated every 10 minutes on average.
Capacity Calculation: With an average transaction size of 250 bytes, a block can hold about 4,000 transactions, capping the daily on-chain throughput significantly below the millions required for mass global adoption.
Layer 2 Solutions: To achieve millions of transactions daily, Bitcoin relies on Layer 2 protocols like the Lightning Network, which bundle millions of off-chain transactions and settle them as a single transaction on the base blockchain.
While the total Bitcoin network (including off-chain layers) can theoretically handle billions of transactions, the on-chain base layer itself remains strictly limited to a small fraction of that volume.
A BTC block can theoretically hold up to 4,000 transactions, though the actual number varies based on transaction complexity and size.
Block Size Limit: While the original limit was 1 MB, the 2017 SegWit upgrade introduced a block weight limit of 4 million weight units, allowing a theoretical maximum size of 4 MB (with a realistic maximum of 2 MB).
Average Capacity: In practice, blocks typically contain between 1,500 and 3,000 transactions daily, with an average block size ranging from 1 to 1.3 MB.
Theoretical Maximum: Under optimal conditions with small, SegWit-optimized transactions, a block can hold up to 12,195 transactions, whereas non-SegWit transactions are limited to roughly 5,208 per block.
Throughput: Due to the 10-minute block interval, this capacity results in a base-layer throughput of approximately 3 to 7 transactions per second (TPS), though Layer 2 solutions like the Lightning Network significantly increase total network capacity.
SegWit improves block transaction capacity by changing how block size is measured, effectively increasing the limit without a hard fork.
Block Weight Limit: SegWit replaced the 1 MB block size limit with a 4 million weight unit (WU) limit.
Weight Calculation: Data is counted differently:
Non-witness data (transaction info): 1 byte = 4 weight units.
Witness data (signatures): 1 byte = 1 weight unit.
Increased Capacity: Since witness data can make up ~65% of a transaction, moving it to a discounted-weight section allows more transactions to fit within the 4M WU limit. This enables effective block sizes of 2-3 MB (and up to 4 MB theoretically), increasing transaction throughput by roughly 1.7 to 2 times compared to the legacy 1 MB limit. Legacy nodes see only the stripped-down, under-1MB version, ensuring backward compatibility.
Witness data in a Bitcoin transaction refers to the digital signatures and scripts (like public keys) that prove ownership and authorize the spending of Bitcoin.
Purpose: It acts as the "proof" or "unlocking key" for a transaction input, equivalent to the ScriptSig in legacy transactions.
SegWit Change: Before SegWit, this data was included within the main transaction body. SegWit moved it to a separate, optional structure at the end of the transaction.
Benefits: By segregating this data:
It is not included in the calculation of the transaction ID (txid), which fixes transaction malleability.
It receives a discount when calculating block weight (1 byte = 1 weight unit vs. 4 for other data), effectively increasing block capacity.