Spotify can play online. However, if you want to download songs to your device, you can play them later offline too. But having lists of songs in your phone will occupy a big oart of your phone memory. This is contradicting. If you want it offline, it can be at your phone memorys expense. If you want it no installation you will need a full internet connection
You're right! I'm also starting to think that some of their concept is contradicting just like for example Spotify as what you've said it's indeed contradicting, when I think the purpose of no installation is to save some storage in our devices.
It is not contradicting actually if we try to understand the whole concept.
You see, PWAs are apps that does not require to be installed before you can use them, since it runs on the server itself and not merely on our devices. But content-aware applications such as spotify gives us a chance to play songs offline by dowoading the music content and not the app it itslef.
I hope this helped.