For convince? There is a single app with all the music, recommendations, and everything. Also, Spotify would be far cheaper. Most people would just use the app with the biggest catalogue, and not a single dime would go to the artists.
Currently due to copyright enforcement, alternative distribution methods such as torrenting are being made as inconvenient as possible to use. If legal enforcement was relaxed, there would quite quickly be some really nice convenient apps and probably a healthy level of competition and interoperability.