It used to be the case that cords you plugged in multiple times a day were reversible, while cords that you were expected to leave plugged in often weren't.
Headphone jacks (1/4" or 3.5 mm) work like this, as do the once-ubiquitous round tip AC adapters. VGA cables, HDMI cables, ethernet cables, serial cables, etc. all required a specific orientation...but that didn't matter because you were mostly going to leave things plugged in. This was the original idea with USB, too - you'd use it for things like mice and keyboards and hard drives and printers, plus the occasional camera...but very few people would be plugging their cameras in 20 times a day. And certainly no one considered that you would be doing this in the dark.
But of course the use case is very different now, so I'm glad that they are going back to the old standard of "frequent use=reversible".
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