>>64120720
Smaller package, low recoil, reduced penetration, quieter, less percussion, shares ammo and potentially mags with your handgun, still very effective.
They have their uses.

>>64120744
Arguably, police only switched to the AR platform (in this context) because of external factors. If you're going to train your police force on AR and have them standard in every police car, you might as well just use a short barrel AR for cqb stuff too. It simplifies training and logistics.