The red light on a camera also means it’s “recording”. Which is the reason the record-action in audio/video software is still a red circle to this day. This being about audio and video recording capability makes this another way to look at it, in a not complicated way.
What in trying to say is that what’s intuitive depends on your perspective. Most of all what you’ve encountered before that’s similar. It had nothing to do with overcomplicating anything.
Scroll down a bit in this article. There’s a list of what each of the available keys are required to provide. A “key” in this context is basically a notch in a certain location, which then defines the meaning of the various pins of the connector. Some devices have multiple keys, as some of the specifications have a common subset. Like key A+E is common, because E provides almost everything that A does, so a device that only requires the common interfaces can work in both. Cars that rely on one of the exclusive interfaces will have the specific key of course. This A+E communication is often used for WiFi cards.
Sockets always only have one key though, for obvious reasons.
Edit: correction/clarification