1) its fun to see the game from a different perspective sometimes. 2) a lot of people come for the environment and banter that some streamers bring to their audience; as well as their ideas, information and so on. 3) because some people aren't really too skilled at said game, but they enjoy it. For instance, I really like The Witcher 3, but Im complete garbage at it. So, I watch Gothalion's Witcher gameplay because its a fun environment, he makes jokes that cater to my type of humor and is informative about the game. I hope this helps you understand why people watch instead of play, I saw this question frequently and many find it hard to answer.