as an example of useful content that will never be removed you can always look at Andreas Antonopoulos videos.
If youtube uses the same algorithm that they use for demonetizing other videos, then it is possible that they remove good content, but I don't think there's that much of good crypto content on youtube to begin with, and most of it is old and well-established, so it's unlikely to be removed. So maybe overall it's a net positive that a lot of scams will get booted out of the platform and less people will get scammed.
i don't think it is an algorithm they use to remove videos from their platform. it is mainly based on reports a video receives plus the topic/contents of that video. for example when someone is advertising an ICO scam or spreading wrong market analysis to mislead people into buying a pumping shitcoin and is reported, the video is going to be removed.
the "good content" even if reported, won't be removed because there is nothing wrong with them.