Playing for cash normalizes gameplay by eliminating some unwanted incentives (in cashless games, there isn't a huge difference in reward for getting second place while being up 30 chips or down 30, leading to unpredictable, over-aggressive play), and ensures people take it seriously.
It doesn't really take a very high buy-in to achieve those goals. When my buddies and I play, we typically go with a $20 buy in, denominated in dimes or quarters.
Like I said, I like MTTs, I agree that incentives is necessary for the game to be playable (i.e players don't play truly randomly), but rewards, at least in my opinion, break games.
If I need to be manipulated for me to appreciate playing, is it really worth? Because we know dopamine rushes have effect on your brain outside of the game, when it's over.
It doesn't really take a very high buy-in to achieve those goals. When my buddies and I play, we typically go with a $20 buy in, denominated in dimes or quarters.