Creators will likely see extra revenue if they make some videos patron-only, at different levels. Some creators will likely get too greedy and lose viewers, while others will probably do fine holding a select few back to attract new patrons.
The bonus for users will be (hopefully) fewer in-video sponsorship ads (I know all about squarespace and nord vpn, thanks), and no algorithms sending you content you don't want. Less discoverable of new content, though. I suppose "click like and subscribe" will turn into "become a patron!", so that's a wash. Hopefully there won't be as much self-censorship, too, because they have another revenue stream if a video gets demonetized. Or maybe they will put the controversial ones on Patreon only.
I'll be interested to see how this turns out. If it becomes competitive, I suspect YouTube will ban Patreon links instead of doing the more sane thing of partnering with them.