I thought it was stability – your feet are more secure as they are closer to the spindle
That’s the Theory, along with a margianl improvement in pedaling effeciency, but it’s all a tad tenuous really. I don’t think you’ll reduce pedal strikes significantly with what2.5mm cinched off each paedal side? plus the platforms are still just as wide which will have more effect on the likelihood of strikes.
Interesting idea about thinner soled shoes, so long as you could maitain stiffness in the mid sole and of course grip, I reckon there might be something to gain…
Ultimately I doubt thin pedals make much difference to the IT Managment crowd but I doubt they do much harm either, the “Fly paper ones are my Favourites so far, now those are properly thin…