does anyone actually want to discover music like this, by typing in what mood you're in or what kind of music you like?

if so, what about something more visual like movies and tv shows?

typing in what kind of music you like and discovering music was the entire premise of Pandora and it was pretty successful.

You can easily comes up with "song/band sounds like X" but it'd be a lot harder to do with movies and TV shows because beyond genre there's a lot of variation in what makes something good. Acting, direction, lighting, story, effects, actors, etc. Failing on any one of those things means I'm less likely to enjoy a show, but being similar in any one of them could cause a match.

That said, if you were to ask for specifics it might be more helpful. Recommending movies based on tone, or style, or story elements might still be interesting but I think you'd still run into the problem where it may not easily result in something you're likely to enjoy.

Yes. All the time.