I used to, a couple of years ago buy my music individually. I liked the idea of owning my music. The problem is, the larger my collection gets, the more unwieldy it becomes. Of course, they have some better solutions for that stuff now, like having a home entertainment server you can use with something like Plex to stream to your own devices. I was just over syncing items, moving libraries to SD cards, etc. I've tried a few different streaming services, and I like them for a few reasons, even though when I started I had my doubts. I ended up with Google Play music for a few reasons. 1) Cost vs value $9.99 a month buys me an individual subscription for unlimited use. Everything just works, whether it's on PC, Android, or Google Cast (which I use). Your playlists work across all devices, and more importantly to me, the Google Play subscription comes with YouTube Red automatically at no additional cost, so no more YouTube ads, and the ability to download videos to phone or play them in the background, which are features I find handy. 2) With Google Play you can upload your own music. Once you do it's available on all devices, and it's still owned by you. I've found I enjoy music more with the subscription because it's a lot easier to discover new music.
Finally, right now, Google is changing things up with Google Play and YouTube Red, making YouTube music. I have early access to it and so far I quite like the direction they're going with it. They've also said that Google Play isn't going anywhere anytime soon.
My two cents...