The latter solely for nostalgic reasons. I actually watched it for the first time as an adult not long ago (bought my sister a copy as a "gag gift"- I do this every once in awhile w/ films she and I loved as kids) and it was almost fascinatingly awful. It has bizarre shit that makes little sense and it doesn't even bother following its own "rules re: being a ghost". Still somewhat entertaining, especially if you grew up on it, but objectively a terrible movie.
I do think "Himself" is a legitimately good standup set, though obviously not among the all time best. The Cos does a bit about how drugs are bad bros!
That's pretty much all I'm familiar with, unless you count his bit role in "Jack" (another truly terrible movie, only with no nostalgic love from me, even though I did see it in the theater when it came out). I've never watched a single episode of "The Cosby Show".