I disagree; Spotify is good at serving up sound, so it makes sense for them to also serve audiobooks and podcasts; just like it makes sense for video streaming services to have both movies and tv shows. Similarly for concerts; people who listen to a lot of music are probably interested in going to see their favorite band live.

Mind you, I definitely have complaints about the app (like notifications interrupting music, their abysmal lock screen widget, and their "randomization" that always ends up playing the same few songs from a list of thousands); but I also understand why they want to expand.