Sure, why not? Eighteen year olds can buy 'em. For close in defensive use they work just great. Plus buckshot won't carry forever and go through walls quite to the degree a rifle round would. Shotguns don't don't have the stigma that an evil assault rifle like an AR or AK or an SKS would.
Also, I'll bet those muskets they used back in 1776 had about the same range as a modern shotgun.