The guns (with what is now called a Raptor grip) were originally designed as police stakeout guns/witness protection guns, but with shorter barrels, since NFA approval on a police letterhead is not a problem. Someone discovered that putting a 14" barrel on a virgin receiver with a Raptor grip brought the OAL over 26, thus not a shotgun (never been fitted with a stock) nor a pistol, SBS, or AOW. When Mossberg, and then Remington picked up on this, the guns' popularity soared. They are a fun range gun if nothing else, a handy truck gun, good in small areas (apt's, RV's, etc.) and can be "holstered".
IIRC, concealing one instantly turns it into an SBS ?) I don't have one, had fun shooting a friend's at the range. I prefer a stock, even on a SBS. An 18" barrel and a stock is fine with me. But hey, I'm not going to say, " because I don't like them, I don't want anyone to have them", that view is too much like the opposition's.