My personal reasoning, which is 100% anecdotal and 100% non-science, is for the reasons Kolie lists:
Doing 60-80 high RPM 30/15s in a workout really makes my hip-glute-leg chain feel more engaged and connected vs a quad busting 5x5 workout, especially if I’m coming out of an “off” period or even a long SS block. I find it doesn’t take many to build those sensations, maybe a couple of weeks. That’s just my perception, which very well may be wrong from what’s actually happening.