I see this as a huge, industry-changing event.
Right now, there's no big DJs streaming on Twitch. There's also no big streamers that became big because they're DJing. DJs on Twitch do exist, but we're talking dozens to hundreds of listeners, a small but very consistent community. I can only name one DJ that can consistently reach a couple of thousand, but she's more of a variety streamer, not exclusively a DJ.
The really big story here is that DJing stops being this legal gray area on a major platform. If record label owners woke up one day with the intention to remove every DJ set from YouTube, or SoundCloud, or Twitch, there's nothing anyone could do about it.
Up until this point, Mixcloud was the only platform available where a random nobody can perform or publish a DJ set without having to worry about it being taken down. The problem with Mixcloud is that most listeners don't want a separate app just for DJ sets, they'd rather listen to them on an app they already use, like Soundcloud or YouTube. So naturally, DJs navigate towards constantly living in this shady gray area, accepting the risk that the community they've gathered could simply vanish one day, despite there existing a 100% legal method that every DJ is aware of.
Now, there's a mainstream platform that has, for the lack of a better word, "regulated" this whole thing. If Twitch does the bare minimum to promote this (as in sign a couple of relatively mainstream DJs to attract a new crowd), I can absolutely see this being very beneficial for the random "nobodies" already DJing on Twitch in front of dozens to hundreds of people.
I will also will be interested if the paycut is variable. I mean should I pay through the nose if don’t stream any big A-listed musicians?