Sending your release to YouTube Music will allow you to publish your music as an Art Track.
An Art Track is a song with an image generated automatically by YouTube. It is composed of the proper sound recording, the release cover and all the metadata you entered in the platform as an user, for example the Artist name or the Album title.
The Art Track is catalogued as an audio for YouTube, that's why the audio is distributed through the platform.
The Still Image Videos will appear in YouTube Music app and Youtube Red, as well as in the channels/playlists that YouTube decide. They are created for their streaming service and their music products.
Also, these Art Tracks are included in YouTube Music app and YouTube Red subscription services.