Coverage

Okay, here's another dumb music-related issue (and I use that term loosely) that no one will care about. Basically, why do so many bands that write their own songs release covers as singles and/or videos? They Might Be Giants did this with "Istanbul," and Mono Puff's only single was "The Devil Went Down To Newport," a cover of a song by some (probably obscure) band called the Clamdiggers. Then there's "Pictures Of Matchstick Men" for Camper Van Beethoven, "Head On" for the Pixies, and "Hang On To Your Ego" for Frank Black solo. I believe the Young Fresh Fellows did a video for their version of "Picture Book," although (as with most of the videos in question) I haven't seen it. I'm sure people can think of plenty more examples; I was just using ones from the bands with which I'm most familiar. It just seems to me like, when a band is choosing what songs they want to demonstrate to the general public, they'd choose something representative. How is a cover representative of a band that mostly plays stuff OTHER than covers?