When I'm tired or climbing hills, sometimes, rather than pressing down on my forward foot at the 2 o'clock position, I pull back with my bottom foot (at the 6 o'clock position) and simultaneously push forward with my top foot at the 12 o'clock position.
This is eminently doable with pinned flats. What I can't do with pinned flats is achieve maximum acceleration. That's when I push down and, when I used clips, pull up. If I raced with my pedals or rode in pace lines, I'd probably have to work harder to catch up after every slowdown. But I'm too slow for any pace line....
I don't mean to push flat pedals as
the solution, just as
a solution, one that is better for many - not all - recreational riders than clips.