Q: I find it weird because it's only possible as a result of a musician already making a complete song that they've published, and then dancers dance to the song, but it's like they're the main attraction instead of the song
A: music is an extremely powerful ingredient in audio/visual content. so, in the case that an artist can't actually do everything, you find many audio/visual situations where the star of the show is indeed not the audio maker per se. or, in other cases, not the video maker per se. hopefully in either case there would be a satisfactory arrangement worked out between the audio and visual artists, financially or otherwise