I am one of those suckers (:sigh) who paid for Youtube since it bundled Youtube Music with it. However, today I used the latter’s Revanced version and it was so much customizable. Right from removing menu items to the stupid cast button Google has forced on us; it seems a billion dollar company can’t compete with these folks who make their apps so much more serviceable.
I don’t wish to go too much into the official Youtube client which too is tacked with things like Remix button and what not.
Alternative frontends don’t fall under piracy by any definition. Youtube’s servers are publicly accessible.