It uplinks to the HUDs.
Pretty much anything can always be explained if you want to make up enough back story for it. Like Snaf used Covie tech as reasoning for the carbine clip. It doesn't make sense, unless you want it too by using some made up reasoning.
And I have no clue what I was thinking with that laser-ironsights comment. I believe what I was meaning to say there's no real need for another irronsights when the SMG already has one.