It must be nice having modern brakes. There is no chance whatsoever of my old side pull Dia-Compes locking the front wheel and tossing me over the bars. I definitely need and use both brakes.

The idea of a bike with just a front brake, or only using the front, seems crazy to me. Using a rear brake is predictable and controllable in all conditions. A front brake is sort of a one trick pony.