It is a two edged sword. For some "things" you need trace…

It is a two edged sword.
For some "things" you need traceability or at least I would want that.

Regarding cash: people will always find something which is good enough to be traded p2p in the real world. Even in jail they found several things and they have much less options in there.
I am not sure, but "the cashless society threat" may just be a ghost to deflect us from other more serious issues.