Well, that is simply not what I experience, having STM lens, old USM lens and new USM lens. I'm afraid your statement is more from marketing materials and official articles than actual real life use.
Just like there are multiple USM types (regular, ring, nano), there are multiple STM types, have a look at https://www.eos-magazine.com/articles/EOS_feature/canon-stm-stepping-motor-lens.html .
So non-ring USM compared to lead-screw STM would likely favour STM for speed and noise. Canon is quite blatant in their press materials, after a while you start to notice that on select lenses they will say "But this one uses the awesome version of <focus tech>", while the other lenses just get the generic blurb.
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