As I understood it (obviously with some exceptions), music videos were an expense for the band/label that fell under the general purpose of promotional material

As I understood it (obviously with some exceptions), music videos were an expense for the band/label that fell under the general purpose of promotional material (like posters, magazine ads, etc.) Of course they were a chance to be creative and have fun as well, but that can be the case for any promo material. The thing with MTV was that it was such a low cost concept for a network. Instead of paying for programming like most TV, music videos were essentially free (if not sold to the network in a reversal of the typical TV transaction). It was like a paid infomercial for bands and albums, except actually entertaining in its own right.