I think some of this also depends on if you are clipped in or not. I have ridden with BMX pedals all year, outside of a few days in the spring. In a way I've no choice but to "mash" as I cannot efficiently use the entire pedal stroke. That being said, I get ever closer to spinning without being attached to the bike, but from what I understand it is necessary to clip in to get full benefit of spinning.

Of course I did just learn how to ride 8 months ago, so am still learning lots of things