This section of the policy is in place to make sure Spotify content isn't being mixed in with content from other services.
To give you a concrete example, let's say you want to display lyrics in your app. Sourcing the lyrics from a separate service and mixing in on the same view where you display Spotify's content like album art and music analytics would be a no-go according to the policy. However, if you were to have a button that opens a new view with the lyrics that does not show any Spotify sourced content this would be OK.
Another example: Creating an app that allows the user to login to both Spotify and another music streaming service is OK as long as the two are clearly separated and don't mix content. Creating a view that mixes content from Spotify and another music service would be a no-go, but having them clearly separated would be OK.
I'm hoping this makes it a bit more clear, otherwise feel free to post your concrete question/use case and I'll try my best to answer.
Let's go with the example of an app that displays the lyrics of the currently playing track (sourced from a 3rd party service).
In this scenario, what would be considered "Spotify content"?
If I were to use the name of the currently playing track to obtain the album art from a 3rd party service, and display said album art alongside the aforementioned lyrics --- is that still a violation of the policy?