That's because you're wearing a mask or goggles. Without those irons are still better in most situations. Games don't translate well as to how good irons really work in real life. And things like ACOGs - the real ones are powered by radioactive material and last for decades. Reddots and such run on batteries. Batteries fail, things break.

Also alot of them outside of some super high-end ones are not that great in bright environments. Also in the military; servicemen have to buy their own scopes for normal infantry. Those things cost well over $1500. That's alot when you're getting paid $15,000 a year.

DMR and Snipers are issued scopes given that they are marksmen and require them.