It is among my most frequently used apps too. Actually, not just on my phone but also on my PC. It relieves the pain of archiving your songs, Spotify has more songs than you could want. It even has retro albums which you would struggle to find elsewhere even if you tried.

Another plus of Spotify is, and in response to Onuralp, that artists also benefit from it. As you mentioned, they receive payment as their songs are played, though I don’t know the details. This is why Spotify is legal unlike Napster and its successors.