We bitch and whine about how heavy the 4$ are, but it really is not how heavy they are in pounds; it is how heavy they feel. That weight felt is due to so much of it being carried to high on the chassis. By lowering the center of gravity, the bike "feels" light and nimble.
Same goes for 2T's. Gasoline weighs about 6 lbs per gallon so we all have 12 or more lbs sitting above the spine of the motorcycle. That is a pretty significant amount of weight.
With EFI, a couple of additional advantages are available in addition to the obvious. First, you have to have a fuel pump. That means you can put fuel BELOW the intake (ever notice you tank never protrudes below the carb?) and thus move that 12+ lbs much lower. Second is, you should never foul another plug since your computer is continually adapting the fuel/air ratio, so no need to struggle with those low slung tanks to continually change the plug. Sure, you might have to remove the tank to do it, but then you'll probably only change the plug when you change a ring!