Music on Twitch like BastiGHG?

I'll take BastiGHG as an example. He always streams music with Spotify, and I can't find anything that says it is allowed. Why can he play it anyway? And most importantly: What kind of music can I play as a Twitch affiliate?

He can play what he wants. It's just not allowed.

Even though he's such a big streamer?

Don't know him. But basically: yes