> I don't know how it's really used in the wild, so to speak.

Commit signing primarily exists because linux kernel development happens via email, which isn't a secure channel.

In that context, signing is used to prove provenance; a commit signed by someone with merge rights gets included, and if you repeatedly sign bad code you'll have your right to merge revoked.

> you can hold me accountable for that commit

I wouldn't personally want to be held accountable for a commit I'd never so much as read, so I would never sign (even locally) a commit until I'd looked at it.