Why are you streaming more and more on YouTube? The Youtubers used to only make videos and stream on Twitch, why are they now streaming on Twitch?
In the past, YT didn't have a stream function, so they stream on Twitch because they're already used to it.
The rules on Twitch are getting stricter and many will get a ban if they have done something small wrong. It's much more free on Youtube
Because it is easier for most, since they already have the majority of their community on youtube and therefore do not always have to make announcement videos etc but get people notified directly when the stream is planned
But YouTube is also becoming stricter, mainly with the general guidelines.
There are far too many streamers on Twitch by now. That's why many also do YouTube livestreams.