As an old coot who occasionally still must dismount and walk up a hill I could not quite bring myself to make the jump to road cleats. Instead I opted for the A520 Shimano sport road pedal. It is a single sided pedal that performs much like a road pedal but uses the MTB cleat inset into the sole of the shoe. I doubt that it has the performance advantages of a true road shoe/cleat/pedal for the longer distance riders but it sure beats the localized hot spot feeling of riding uncaged MTB pedals on a road bike.
The largest advantage to me is the ability to use the same pedal/shoe combination on all of my bikes.
I do envy the lightness and quality of good road shoes however. As with most parts on a road bike, optimized for power and speed.