Other than the historic perspective, I've never seen the attraction myself. Back in the '80's, I owed several (converted AR-15, American 180, Sten). Shot them a few times, made a lot of noise, kicked up a lot of dirt, missed a bunch of times and got bored.
I'm glad I didn't dump them back then because they because quite valuable and earned me a nice margin when I did sell them a few years back.
I guess my resistance to the whole spray and pray concept is why I didn't particularly care for them. A tacticool mall ninjas dream come true I guess. *shrug*
Wouldn't the "tacticool" mall ninja types have fun if they were still easily available today?