This reasoning never made a ton of sense to me. Gen Z don't use devices with knobs and buttons anymore, therefore we should all design our interface elements to look like nothing in particular?
If you give someone young and tech savvy a digital UI, they will figure out how to use it. It's precisely the oldest and least tech savvy users for whom interface design is most important, as they are more like to get frustrated and quit your app. Why optimize for the young, then?
(I mean, it's a rhetorical question, as I already know the answer - the designers creating the interfaces are themselves young and tech savvy gen-Z'ers.)