Mainly, Americans came under fire from PKM machine guns, mortars, and heavier anti-aircraft guns like 14.5mm and 23mm weapons, which outgunned their 300 meter M4 carbines. As a result adding a marksmen to every squad was seen as a good idea, and the marines had already incorporated marksmen in to their squads some time ago back in the 90's. The issue is not that the taliban were outshooting us with sniper rifles or ak-47's per se (although some were using dragnuv's and such), but mainly the really large machine guns could provide saturation fire on american positions at far longer ranges than assault rifles could. A lot of times it was like, 800 meters away with an AA gun which is not that far, but is still outside of the range of a 5.56mm. So, they figured a marksmen could really help a lot, and they did. Technicals are very common, and they can be taken out with regular rifle fire. In fact, a .338 Norma machine gun, at just 24 pounds, lighter than an M240 at 27.5 pounds, has become a thing for similiar reasons. [1][2][3] The range advantage is real. Same range as a .50 cal but man transportable is pretty great. And there's not much of a need for armor penetration, so you don't need it for anti-material purposes, just anti-personnel. The particular .338 gun has a recoil counterbalancing system and is usually mounted on a tripod, so the recoil is pretty light. Long range precision shooting for automatic weapons is becoming increasingly more of a thing, and in my opinion is a great idea.