yeh -on models - it is simply a looks thing-
even on the full scale stuff going back to the 1930-/40 etc., airshow daredevils- the wheelpants were among the first things to go -They simply were extra weight .
The Bucker designs - the best in the world for aerobatics for many years - used only tiny mud catcher fenders.
for max cruise -best speed/ least fuel consumed - streamlined covers do help --on some full scale stuff .
The best trade off design is probably the one used on the Sukhoi 31-- a tiny wheel fairing, behind each main wheel.