I guess you could say parallax will degrade your precision at shooting a target. But at 50 yards or in (even 100 and in) , id say yes, even with the worse parallax it would be faster than irons, as you dont have to line up 2 things (rear aperature, front post).
Also if were in a weird ass position, firing on your side under a car, or something, and you cannot get a good cheek weld to line up your front and rear sight, what would you do vs having a red dot and maybe 1 or 2 inches from your poa to poi? No hostages in that scenario. LOL. I believe all optics were made so youd only have 1 point of AIM/ reference to shoot (put the dot, crosshair what have you) on your target. Sure there may be minimal shift from poa to poi. Better than nothing DEPENDING on the situation at hand.
Dont quote me on this, (i saw this on a video where someone tested parallax with eotech, holosuns, t1 etc.) I mean he tested like 10-20 different red dots. Anyways, with aimpoints i think the parallqx only affected less rhan 2 inches at 100 yards. Thats sort of minute for a man sized target. And that was with live fire. I cant speak for the PA m4 clone tho. I was just researching holosuns at the moment.
Everyone is different, maybe you can shoot faster/ very well with peep sights, aperatures. But i cannot compared to a red dot.
By no means, im saying the miltary is the gold standard, but if you just google or youtube and spec ops training, from breaching to sniper training , anything except basic training, everyone will run some sort of optic. Even 3 gun, when i watch, everyone has an optic. Lpvo for long range, offset rds. The transition to a rds is faster than turning down the zoom. (I think miculek says that too) Even law enforcement in the mainland are running rds on pistols. Not all departments, just some. My friend is and he lives in the middle of nowhere georgia. Its faster i think?
Lpvos are great, dont get me wrong, i have 1 accupower. In fact i went through 3.and a p4xi and a leupy VXR's 1.25-4 german 4, and circle fire dot. I do not like the mere size of it. I would choose a 1lbs acog over a .5oz 1-4. (Major exaggeration, but kinda hard to explain for my preference) i kept getting them and selling them. Kept on takin losses over an over again.. So i said fuck it already, im not going to sell my last 1. Cause i know ill get another 1 again. So i made a special ar15 just for that scope. Hardly shot it tho.
Honestly speaking, if i had time to aim and take my time on that trigger. 100 yards or more, id take a scope indefinitely. If i was in iraq id take my acog and offset red dot. But i dont wanna run anymore so you will never find me there lol
Edit: maybe im just trying to say speed is sometimes more of a factor than a super precise shot. I can put holes on the bullseye with red dots at 100 yards if i take my time. My co workers and friends can back me up on that as they were spotting for me.