They don't really work for me. I listen to different genres, different languages. Sometimes I only like a single song from an artist. My taste is weird. I usually discover new music organically through friends, or sometimes I'll hear something playing somewhere and stuff.

To me, it seems like the Spotify algorithm has a heavy bias towards newer songs, and also towards English songs. Both of those are a minority in my playlists, but somehow that's all it recommends me.