Are sights/optics necessary on ARs?

I've always used an optic on my ARs, but I'm now considering dropping it and just using the iron sights, so that I can add another attachment to improve the gun in other areas.

How necessary do you feel optics are on an AR? It's obviously nice to have a precision red dot sight, but I'm now wondering if I'd be better off just using iron sights. Do you think gameplay and performance wise that players would be better off using iron sights and improving the gun in other areas, such as recoil, ADS speed, etc?