how much resources would a state employ, to go after a random citizen who might have spend 50 bucks of BTC on a dinner, without declaring capital gains on it?
They won't go after one particular random citizen, they'll just analyze everything they can and see what comes out.
Then there's the consideration that KYC is a huge security issue for end users (hacking of exchanges, data leaks, etc). A person doesn't need nefarious reasons for wanting to improve their anonymity.
Obfuscating your current holdings won't change the potential risk from a data leak.