An acceptable substitute? No. As a means of augmenting leg action in slowing a rear wheel? Has some merit.

My view is biased by a crash I had 14 years ago when a clipless pedal released spontaneously on me at speed, which caught me quite by surprise. Had I been riding with my hands on the hoods, I could have slowed the rear wheel down and brought things to gentler stop. As it was, my clipped in right foot became the lever the wheels and cranks used to pitch me into the bars and over. My last ride on a fixed-gear using clipless pedals, but that's a whole 'nother story.