I agree 100% Tom. My hand is just over 4" wide. The barrel is only 3" long, and part of that length is inside the upper. It didn't take me long to do the math.
If it didn't have a 4" handguard and a blast I could see a
real problem there. As far as suppressing it goes, maybe if you wanted an overall barrel and suppressor length of 7" or so with one of the mini suppressors it would work. But it would still be bigger and bulkier than a pistol.
ETA: Maybe they made it just because they could, knowing that sooner or later someone is bound to buy it. George Carlin once said something like, if you nail together two pieces of $h!t that have never been nailed together before, some schmuck will buy it. I think we're looking at those two pieces of $h!t right here. Someone will buy it.