You can only monetize your vids after getting to 1000 subs + other requirements, which is the hardest part, until that yeah there is no reward, on Twitch I guess its easier and faster to get to point where you can get something out of it.
After getting approved to monetize on YT any video you have previously uploaded or anything else you upload from that on can be monetized and can continue to make money forever there as it keeps getting views. On Twitch you can get a lot of money sure but then you need keep streaming for hours straight, engage a lot with your views, this and that, and if you stop streaming you stop making money right ? Its always proportional to the amount of hours/work you are putting into it right ?
On Youtube you dont need to keep uploading to make money. Sometimes an old video you have monetized gets chosen by the youtube algorithm at random to blow up and you gain money simply by the luck of having uploaded that years ago. Youtube videos can work like an investiment, any video you throw there and monetize has potential of keep making you money as long as the platform exists.
I think that Twitch can be faster to get started but YT has more potential on the long run.