So, wait, why are clips and straps automatically better for fixies, especially with hills?

And why is a pedal system that allows you to transfer full power at all sections of the pedal stroke less efficient than one that doesn't?

It all comes down to preference, as far as I'm concerned, and personally I noticed a world of improvement once I switched from clips to clipless. I'm just really confused by the rationalizations for the above two arguments.