Just an example of local storage. Nothing special re Spotify.
Equally if you have 5,000 apps taking up 50GB or 100GB iCloud isn't going to do anything to help you. The phone will encourage app offloading to give you more space but ultimately iCloud won't help you.
iCloud won't give anyone more local storage, it will just put into the cloud what is possible to live in the cloud -- photos, videos, backups, contacts etc.