Not a fan of either to be honest but it's fine. I'd rather listen to music than audio books in most occasions but I can see the appeal if you're on the road a lot. And watching someone else play games is something I don't get at all. Especially in gameplay-driven games, like, watching a complete walkthrough of a Mario game? Why? But if it makes you happy, do it.
However, I have this weird friend who watches complete walkthroughs of games, plays them a month or something after that and then complains that he doesn't like the games or simply stops playing them because he knew what was coming or some bullshit like that. Leaves me clueless what's wrong with him.