The thing I've noticed is that extended conversation with AI can be numbing to the mind, almost like after you've played Tetris too long.  You're thinking in a disassociated way.

So for therapy ... not sure about that.  

They're like a handful of Prozac, maybe it's good for some, but probably not for most.  That said, I think a lot of people are actively using them for therapy, whether intentional or wise, or not.  The new addiction.