The only reason you listed was its lack of penetration but it seems that it does still over penetrate and the effect of the longer firearm is a major flaw for home defense.

so if you wanted an actual gun that didn’t over penetrate a handgun with frangible ammo is the much more logical weapon, is it not?

Compared to drywall the effect of air resistance is negligible so the spacing on the dry wall sheets is essentially irrelevant.