Perfectly said there @Pork_Rind ! You beat me to it.
Here’s a parallel explanation I’ve had simmering for a bit, but wasn’t on my PC to write.
Here is a typical PC 110v power cord:
You’ll notice the two ends are different. Why? After all, it’s just 3 dumb wires carrying power; not even data.
It’s because the designers don’t want you to take a cord with two male ends on it and plug that into two powered wall outlets. Bad things will happen. So they don’t make cords like that. They sure as heck don’t supply cords like that with PCs.
They also don’t want to make cords with two female ends on them. Because then some goofball would plug two PCs together with that cord and wonder why they don’t both work.
The physically different but electrically identical ends are to moron-proof the hookup. Nothing more complicated than that. Back in the day when adding intelligence to the cable or to the dumb device end would have been prohibitively expensive and/or bulky.
The traditional flat USB-A connector and the square USB-B connector are exactly the same idea. When only A-B cords are made, and all devices that supply power are designed with A connectors and all devices that consume power are designed with B connectors, then the entire ecosystem is idiot-proof. If the big clunky plugs and sockets mate mechanically, the power & data arrangements will be correct also.
It’s no deeper than that.
Now after that, of course the Chinese quickly realized they could make shit cheaper by ignoring the standards and everybody else would be dumb enough to buy non-compliant parts. Then USB3.0 got invented, and USB-C and all the rest. To the point that USB-C is now almost more of a battery charging standard than it is a data transmission standard. Almost.
But all of that is just distraction from the basics of the original flat A connector and square B connector designed to prevent plugging stuff together wrong.