I sometimes feel like I'd rather have shorter cranks on my road bike, as my track bike just feels better to pedal with 165s versus 172.5s on the roadie but haven't had the means to try it. There could also be a multitude of other things at work there. Shorter cranks don't require as much movement at the hip to spin, so it does make sense that they'd be easier to pedal at higher cadences. Interesting little convo on crank length from a bike fitter's perspective here, around the 4:00 mark: