I agree, but there are people who create bank accounts (and I'm sure Coinbase accounts) with fake ID and use them for illegal proceedings. So while we can trust that the transactions log is accurate, it doesn't always prove a link to an actual person. My concern is someone having their identity stolen (or even just impersonation), used for KYC, then being linked to crimes without any deniability at all.

Edit: like IP address and torrent lawsuits etc.