Unutilized. Extra $$$ for no functional benefit. Downside: heavier forearm, decreased ergonomics, heavier OAW.
Free-floatrd barrel?
No, actually it has a knights armament or clone hand guard. Non free floating. Basically an A2 with flat top A3 upper receiver.
That said, the ACOG is a decent optic.
I shoot NRA /CMP High power and my A4 clone has a issue pic rail hand guard over a white oak free float tube.
With 75 or 80 grain long loaded bullets for 600 yds, it keeps them under a minute if I do my part. The leupold LPO certainly helps but I use irons as well for the mid range prone strings when required.