How does riding on bumpy road while suspension fork locked and without slow down effects? Is urban riding on bumpy road while suspension fork locked and without slow down harming to my bike or me? I don't care about my comfort so much. I don't want to slow down or to lose energy.
On a bumpy but fairly level road, absent any suspension, energy goes three places:


Friction between tire and road
Wind resistance
Vibrating your body up and down


The reason #3 is a factor is that you jiggle as you ride, and that absorbs a lot of energy -- the more you jiggle, the more energy is required.

You can reduce jiggle by using lower air pressure in the tires, but this increases tire/road friction.  You can add front and/or rear suspension to reduce jiggle, but the suspension itself absorbs energy, plus it tends to make pedaling less efficient.

So it's a tradeoff -- at some point in the transition between smooth and really rough roads it probably pays, in terms of energy efficiency, to unlock the shocks.