Aero wheels give you incremental speed. Just like a previous poster said, just like a aero helmet and according to specialized, if you have hairy legs, shaving them will give you the same benefits (at zero cost). All these little benefits add up to a significant time for racers, for recreational riders does it matter?

add aero full carbon wheels cause they look nice, if that has a placebo to make you ride faster and more, then it might be worth it.