Interesting thread. Is this a [relatively] new technique for clipless pedals/pedalling v.s. toeclips? Or maybe just new thinking?
I remember in the 70's we were all trained to ride toes-down. We used toeclips and old-school cleats, but the technique was definitely toes-down about 30 degrees. Pedalling with the feet flat was snickered at, now it seems to be the opposite.
I can't remember the rationale for riding toes-down; something about muscle/spinning efficiency...or something. I still ride that way now. I must look like a total gomer, but it's a hard thing to change after 30+ years.