If you ride only paved surfaces, there is not much problem to use front brake, I think.
The main problem (from my extensive off-road background) is braking on curves or slippery terrain, where you should take a bit of care not to block your front wheel and fall from the bike.
I am not saying the front wheel should not be used on curves, or on unpaved terrain, only that extra care should be taken to modulate front and rear brake forces so as not to block and slip the wheels (unless, of course, you want to skid the rear wheel on purpose to correct your trajectory, which is a very useful menoeuver sometimes).
Also, when you go down a curb, specially when going down a slope (for example, going from sidewalk to street), brake modulation and demodulation might be useful too: when each wheel is "in the air" between the two different height surfaces, the brake on that wheel should be quickly released, and just AFTER that wheel hits the ground it should be used again. It helps not to tip over the front wheel, and not to skid rear wheel (I care about my tires).
Hope it helps!
PS: and just to answer your last question, FOR SURE you should use your front brake abundantly! It is the front brake that saves lives (yours and others')