I don't think it will shut down crypto youtube channels only the advertising at the beginning. If their content is about crypto they are only giving their option on the matter. So it's freedom of speech. The same as facebook did it was only for paid advertisement.
I have my faith if they will ban cryptocurrency ads, the only ads will be banned is all about scam project.
Google will do their part by stop the ads of scam project. This is good to prevent people not fall into the scam project.