I'm not going to ruin this by mentioning how many paymails …

Are user IDs backed on chain?

I'd imagine in the future when people are making money from just transactions alone we will have to claim tax that will be automated from our accounts , not so much by our names but account numbers .

Good question . Most likely linked to Paymail linked to moneybutton linked to handcash linked to and linked to. How else will we pay taxes ? Has to be a chain of identity in some kinda way 😉 if we have an account w all these wallets and platforms .

I believe so; https://blog.moneybutton.com/2019/05/31/introducing-paymail-an-extensible-identity-protocol-for-bitcoin-bsv/