One reason is the same as people watching football or basketball, but rarely or never play themselves. These streamers are really skilled and it's interesting t

One reason is the same as people watching football or basketball, but rarely or never play themselves. These streamers are really skilled and it's interesting to see their skill level. Often times these are tournaments like e-sports, and this no different than any other sport. Another reason is just entertainment value. The player is funny and interacts with viewers, or the game genre itself is entertaining to watch. For example horror games, it's fun to watch streamers get jump scared. Yet another reason is to preview a game before buying it. I watch dozens and dozens of streamers, and at this point I think I watch more games (by title) than I play.