It’s an important milestone as it’s the only effective way to make PC gaming available on operating systems other than Windows (i.e., reduce one of the Windows monopolies). Still, Linux gamers shouldn’t take it too far. I’d advise everyone to still not support game studios which are openly hostile towards Linux gamers. This especially includes the ones who rely on client-side anticheat tools and then use those to block Linux gamers even though the game would run perfectly fine on Linux as well. Please do not support such games or studios (e.g.: Epic Games, EA, Bungie, Riot). Thanks to Proton, there is still a massive number of Windows games that can be played instead.
Probably because Google is actively and frequently banning many Piped or Invidious hosts, and is generally currently at war with “alternative frontends” to YouTube in an effort to make users browse YouTube directly and consume ads there, or buy YouTube Premium. This is in line with their current fight for more ad revenues across their products and services. You probably have to either search for another public instance which isn’t banned (yet) from accessing YouTube, or host your own instance.