I ride platforms about half the time and clipless about half the time.

1. I can't spin as fast on platforms. It's difficult and uncomfortable. 95rpm's is not fast spinning, for some people that's a slower than normal spin.
2. I can stand and pedal just fine on platforms.
3. My feet don't get thrown when I shift, you learn to time your shifts no matter what system you're using.
4. I can't dig in as hard when I stand on platforms. On clipless there are times when I'm pulling and pushing and twisting, etc. It's called a steep hill and too high a gear (in my area it's because I screwed up, but there are places with hills where it'd be because you're in the granny gear already).
5. Clipless puts your foot in exactly the same spot every time. The spot you've carefully figured out is comfortable and has good power transfer. With thousands and thousands of miles on platforms I can't say that I can put my foot in the right place every time. It's close, but when you start hearing squeaking and realize your foot and moved inward and is rubbing on the crank...
6. I definitely use my quads more on platforms. I don't think it's as efficient of a pedal stroke.

So, in my opinion: Clipless lets you spin faster and use more muscles. It's more efficient.

Is that efficiency necessary if you're not racing? Nah.
Is it nice even if you're not racing? Yea.
Is it always worth changing shoes? In my opinion, no.


I would love somebody to try and throw numbers on this. If I owned a power tap I'd probably throw the bike on the trainer and ride threshold (by heart rate) for 5 minutes and give you my average power. Then do it with the other pedals. If a half dozen riders did this we could get an idea of what clipless pedals are or aren't doing for us power/efficiency wise.
That wouldn't cover max power, stability, or spinning speed though.