I only watch people play through games that I don't have the time for. La Mulana for example, it's a super intricate metroidvania with tons of puzzles that require a lot of attention to details. Unfortunately I work a very busy and tiring job and also have a wife and kid so I don't have enough free time to dedicate to the game of that magnitude. I watched a play though of it by someone who edits out a lot of the times they're banging their head against the wall on the puzzles and he's pretty funny as well. It's nice to relax with instead of a tv show sometimes when I unwind at night.
I still play plenty of games, just ones that I am either familiar with or don't take a significant amount of time to enjoy fully.
Now twitch? I don't really get that either. I'll check out some stuff occasionally, but it's just so boring unedited.