I mainly watch for fun but it is good to see the scenarios you come up against all the time... seeing every hand is cool too, not just 'highlights' if you wish.
Lots of good players streaming these days on twitch. I have found it to be helpful to watch, as the good players often explain what they are thinking as they go through the hand which helps me consider how I approach certain spots/hands.
RustRock is hilarious. I caught his last stream on Stars and he was singing goodbye my lover by James Blunt!
Pokerstaples for me has changed he used to be very genuine now it feels like he is just trying to push his on fame and products which I really don't like.
I like:
Kevin Martin
Tonkaaaap
Bulhero
I will watch others when these aren't streaming but for me they are the better ones.
I watch for entertainment but I do think you can get a lot from it. so with that in mind, I am following 3 or four of those listed and plan to watch a little more often my game needs help