You never get to verify that they key you’re signing with matches the key on your correspondent’s device. You are trusting Apple with it, and they could be comp

You never get to verify that they key you’re signing with matches the key on your correspondent’s device. You are trusting Apple with it, and they could be compelled to MITM your future conversations. This is in contrast with, say, Signal, where you do get to compare keys (and it’s open source with reproducible builds).