Why do people use Spotify ?

Half of my Instagram friends use Spotify I love all of them Pandora , YouTube music , Apple and spotify I don't see the difference in any of them. I can't use Spotify much because I can't afford premium right now I been trying to get a new card but everything's hectic right now and I been busy. I love Pandora the best since I been using it the longest. I can only use Spotify regularly on my tablet or Xbox for now. My phone has the ads and 6 skip limit. Why do people love Spotify especially teenagers ? Why is it better and what's the difference ?