Yes, I see what you mean, but if that's really the intent, then having only this font-family rule isn't sufficient. For that argument/reasoning to hold up, it would have to be accompanied by metrics adjustments to compensate for the massive differences between some of the listed fonts in these stacks.
Absolutely true. In fact (and thank you for getting me to think about this), font stacks without metric adjustments don’t really make much sense, do they? (Unless confined to a list of fonts that are very close metrically, which they never are.)