The ability to download music allows Spotify Premium users to listen to their tunes without streaming it over a Wi-Fi or data connection. Subscribers can listen to songs and podcasts whenever they want, wherever they want. Learning how to download songs from Spotify is typically something we recommend early on, so new Premium subscribers can take full advantage of the feature as soon as possible.
Can you listen to Spotify offline without Spotify Premium?
In fact, when I stopped subscribing to Spotify Premium, this was the feature I missed the most.
Read more: How to add songs to a playlist on Spotify