Does anyone know the state of the art when it comes road-style and MTB-style pedals? Are there independent scientific studies which quantify differences in pedaling efficiency? The best I could find was this video on the Bike Fit Advisor channel that discusses some potential advantages (e. g. greater surface area, different pedaling mechanics and aerodynamics) but basically claims that (1) there are no studies known to the author of the video and (2) there are no appreciable differences in his opinion as he thinks the main contributing factor is the stiffness of the sole.
Background: I have been using MTB-style pedals for years and have internalized how to clip in and out. At one point I would like to replace my current pair of shoes, and I am considering getting road shoes and road style pedals. Sticking with MTB-style pedals would mean I could continue to use all of my bike shoes with all of my bikes, I’d have the same mechanics on all of my bikes and I would retain the obvious advantages MTB-style shoes have (I can use the same shoes on all of my bikes, it is easier to clip in and out, it is much easier to walk on them without looking like a duck on ice). Plus, there is no appreciable weight difference between a pair of Eggbeater pedals and, say, Ultegra pedals (280 g vs. about 250 g).