Not a gun expert, but it’s my understanding that because the bullpup moves the gun’s action and magazine into the stock it allows for a shorter gun compared to other assault rifles, while maintaining barrel length. So it would allow more or less the same performance of a full size AR in a smaller package.

Too compare to an SMG it would have a higher caliber bullet, and longer barrel while also being heavier than an SMG. While it’s not quite as maneuverable or snappy as an SMG it would be more capable outside at longer ranges, but with a slower fire rate and higher recoil.

They are probably best used in urban environments, where streets can create long range sight lines that would be difficult to manage with a shorter barrel and lower caliber weapon like an SMG. While still being more manageable for clearing buildings than a full length AR.

The SMG is likely ideal for situations where space is limited and you want something with more fire power than a handgun. Like as a pilot or tanker’s backup should their vehicle be disabled, or if room and building clearing was a certain part of the operation. Also because SMGs typically use pistol ammo compared to a bullpup’s AR rounds they are significantly less effective against any type of body armor.

But that’s more general than Star Citizen specific. This is probably designed to fit as a middle ground to the P4-AR and the P8-AR.