. like, in what circumstance is it better to watch someone else play a game rather than be the player, can someone explain?
Same about watching sports?
As Gravoth said it can have entertainment value: when you are actor you dont react like if you were spectator.
Also you may not have access to the played game or cannot reach the entertainment level the streamer has (skill, PC quality, his friends + the crowd); sometimes you just dont want to play but you would watch a video instead. Thats really perfectly standard procedure applied to videogames.
Now of course, if you have the game, want to play it, and have the option to watch someone play or do it yourself, yes of course its better to play the game