It's a highly adaptable all purpose modern sporting rifle. That adaptability is what makes it so popular I think. The purpose of this "modern sporting rifle" has been a topic of much discussion.
I would think that it’s a primary contingency weapon for close-in defense of your home and neighborhood. I.e., a combat weapon.
It is certainly capable of filling that role. It's capable of reaching out beyond "close in combat" distances too.
Mine was out of the gun safe last night in case the Baltimore entertainment spread a few miles south.
The rifle and scope you have chosen would certainly serve you well in that case. I typically prefer higher magnification variable power scopes. I just can't justify $1,300 for a fixed 4x power scope no matter how good it is, especially on rifles that I have built to shoot MOA or better, rifles designed to exploit chinks in the armor.
Four power or not, I have been very successful out to 300 m. More difficult to distinguish small targets but excellent field of view, good edge-to-edge sharpness, good low light capture, etc.
The main value of the ACOG is the “both eyes open” viewing and aiming technique that really improves fast acquisition of targets in all light.
The main advance that the ACOG in its Rifle Combat Optic (RCO) guise has dramatically improved combat effectiveness for the Marines and other forces that use it.
Consider too, resale: ACOGs routinely sell used for $800 and more. The other scopes rarely retain their value as well.