[pineapple888]

Well, I won't go into detail on every point, but I can state with 100% confidence that there are players who use deception (as I define it) for no discernible purpose whatsoever.

I would expect such an approach to be -EV, and would not call such an approach an "art".

I think we are essentially agreeing, I just prefer not to assume a player who uses deception knows what he is doing or why.