YouTube Premium quietly goes up in price to $14 per month | That’s a significant $2 increase with no official announcement.::Google has quietly increased the price of YouTube Premium by a significant $2 from $12 to $14, according to the updated signup page…
So YouTube premium subscriptions do pay creators even if they are demonetized, demonetization only cuts creators off of ads, premium basically pools all the watch time and divides your subscription(after Google takes its cut) to creators, this generally means creators earn more from a premium subscriber than a ad subscriber.