The Spinsight analysis is true from a physics standpoint, but it misses some of the practical issues involved. That he can get a brushy loop at 130 rps is impressive (though probably against backspin, whichI haven't tried), but the advantage of spinny loops is precisely that they don't have speed so the angle of incidence after hitting the table messes up the timing of the blocker.
The feedback element is very spot on, but I think it also has a few other dimensions that I cannot discuss because I don't fully understand them and because they would take too long to discuss. I am a big fan of measuring blade frequency because it helps me know when a blade is going to be close to unplayable (the exception have been Hinoki blades). Usually, once a blade goes about 1400 in frequency, and even sometimes 1300 sometimes. I know I will struggle to use it even if I can use it and probably will need to use it with sticky rubbers.
I also don't think it is all about looping but about equipment that enables a wide range of shots. Pushing and blocking especially to piggyback on Dr Evil. That's why the traditional advice is still to get the fastest blade you can (short) push and block with (aka control).
I'm not saying slow, spinny loops are easy to deal with, they certainly present their own difficulties, just that people need to be a bit more careful about talking about spin and speed as if you can only have one and not the other. He did it against block, BTW!
As for blade frequency, it hasn't been super meaningful to me. I have 4 Vis variants (1 Vis, 1 ZJK, 2 FZDs) and the lowest weight FZD (89g, same as the Vis and ZJK) has the highest frequency at 1475 and is the most flexible with the best feel. My Q968 is only in the mid-1300s and it's got loads of power.