Small or hobby creators, who aren't making money anyway, could use small platforms - but then they forfeit their chance to ever become big and get that money - at best they could become big and not get that money.
Even more annoying is that it terminates your YouTube account entirely, so now I can't even login to use it. And I was a premium subscriber, too!
The best thing about YouTube is their agreements with rights holders to allow music and revenue sharing easily, which makes it very simple for creators and remixers etc to not get their stuff removed via DMCA.
Youtube's biggest threat ever died in the cradle because they foolishly thought users would volunteer money to them.
No one with capital and capability looks at youtube, looks at youtube's audience, and says "Yeah, 30-40% ad-blocking and 4.5% paying for premium, these are the people I want to build services for!".
Those are the people who will happily go to an alternative product. And while that product might start as a pirate YouTube, the one that nabs 30% of YT's traffic can certainly make a pivot to legit. If you're a content creator whose audience is mostly in that group, you're likely to start posting content directly on the competitor's site.
I'm guessing OP had their account banned for using a tool like yt-dl too aggressively. Then again, doing that does give a warning.
I explained exactly why I think they are important in that entire paragraph. And the evidence I'm right is the fact that YouTube could trivially prevent ad-blockers tomorrow, but they don't. They've tried it and quickly rolled back the changes. Presumably they lost a lot more audience than expected.