From my view, I enjoy watching Twitch for two main reasons:
For the same reason I like watching live sports rather than a 15 minute cut of highlights - the feeling of experiencing events in real time, the payoff of seeing a big play unfold after all the anticipation leading up to it, watching strategies and counter-strategies unfold in real time, that kind of stuff.
For the same reason I like watching video essays, stand-up comedy, interview shows, podcasts, or other media where one particular person is the focus - that person is entertaining to me. They have a personality I vibe with, they’re funny, they have an interesting perspective, etc.
To a lesser extent, it’s also nice background noise. I can throw a stream on at the beginning of my workday and not have to fiddle with it until I’m done with work, because it’s a constant, reliable source of background noise.