We are fighting a very unconventional war, and will continue to for many years to come. This means everyone is a target, civilian or military, rifleman or doctor.
One strong possible reason besides making them less of a target at distance, is to improve moral and recruiting. I would be more interested in joining a branch of service that used a BDU style uniform like the other branches. Just wearing work clothes, etc... would not instill as much motivation as a uniform that looks cool. Just like the same reason we wear our uniforms and gear in Airsoft.
If this is what our fighting sailors want then I think they should get them. I am sure they have conducted many surveys from Navy serviceman that are interested in this change.