You still need to do quite a bit of tracing; only the people who actually go digging and have access to internal data records of the KYC endpoints would be able

You still need to do quite a bit of tracing; only the people who actually go digging and have access to internal data records of the KYC endpoints would be able to trace it. For the uninformed, all transactions post to a separate address, so you'd have to correlate which addresses seem to be used together in various other transactions to tie transactions back to a single "wallet". (Ackchyually that's not entirely true; there are some low level details regarding UTXOs and HD wallets, but in practice you can assume it works like that). And I don't think anyone (who is worth listening to) is advocating BTC for trivial transactions; it has already solidly cemented its role as a "wire" service for larger transfers.