With AI assistants on our phones, it can be hard to tell the difference, and people often use it for completeness or clarity. Blind AI rephrasing has a cost though, sacrificing your personal voice, and often resulting in overly enthusiastic and repetitive sentences.
We've long passed the point where I can tell a good AI comment from a real one at a quick read through of a comments section. It's only the blatantly bad ones (blocks of listicles we delve into) which stick out like a sore thumb. That said, I think that says more about how good AI has become than it hints all the long established accounts in this thread using one just because they could.
(re-reading this, it sounds just like AI!)