Tildes has this feature, and I love it. There are a bunch of tags that can be applied to comments, both of the "this is a brilliant contribution" and "this is noise/low effort/silly" varieties.

In general, Tildes culture is high effort, but there's still room for fun. It's nice to see each platform innovating.

Yes, this would be an excellent feature. Only problem is people exploiting it to hide or ridicule legitimate responses they don't agree with. But that's a problem for later. With the cussing userbase and growth rate this feature works be great for quite a while.