Who were they intended for? People who buy records.
What was their purpose? To sell records.
As I’ve mentioned in other posts, we sometimes forget that selling records made money for the record companies (and sometimes the artists) years ago. Concerts were pretty much for the purpose of promoting record sales. Sometimes tours made money for the artists, but the tours were also a handy way for the record companies and promoters to screw the artists. (“Oh, yeah, we sold a lot of tickets. After deducting all the expenses for the tour and promotion we advanced you, here’s your $27.15.”)
The reverse is true today. Hardly any money in streaming, but shows and tours can rake it in.
We watched Midnight Special for the videos in the mid-1970’s. It aired on NBC Friday nights immediately after Carson’s Tonight Show. When MTV came out, my first thought was it was just a longer version of MS. Reading up about it, I forgot it was mostly live performances. However, as mentioned above, Queen’s Bohemian Rhapsody was played frequently.
I looked them up on Wikipedia and, wow, they are a New York City band. They look and sound like the Alabamiest alabamites that ever ala’d a bama.
I think that they are popular on those YouTube reactions because they are forgotten one hit wonder, and people are surprised to hear such solid tight music coming out of a bunch of backyard yokels that looks like them.
What you’re all missing when thinking about music videos as an early form of promotion was the possibility to air them internationally, without the band having to travel (often overseas) to be played in a foreign market. I remember German music shows from my childhood like Disco and Musikladen (both 70s shows) that usually had the artists performing in the studio, but also often played videos by international bands that were too expensive or where it didn’t fit their schedule to appear in the show. It was a mix of actual promo vids (what we call music videos today) and tapes of performances in other music shows (often Top of the Pops).