Where does this ideas of using more muscles being more efficient come from?

I only mentioned 95rpm because it was the number the other person used, spinning faster is no problem, if you can't then clipless are probably better for you then they are for me. I personally also like the fact that I can place my foot in different positions and having my foot come of in any situation has never happened.

Yes, on a hill where you can't spin at a reasonable rpm and have to mash, then clipless will be better speed wise because you are conciously focusing on pulling up.