Whatever a song needs. If a song sounds better when Krist plays guitar, that's the way it is. I don't think I've seen them all. Carlton Kim has a great one. I can't remember the last time I looked at a Nirvana web site.
Sound quality is poor.
It just depends on the motive of the person of the person doing it. If they're out for profit, they're stealing. It doesn't have a lyrics. It's about how it's hard, but you just have to go on, because it's going to get better. It was only shown once in Seattle, live band accompanying it.