Now I have to buy an USB-C to USB-A adaptor to plug USB-C stuff into my already standing devices. Honestly, no idea why didn't they make it connector-compatible. Wasn't that the entire point of the "U" in "USB"?
Nah, the point of the “U” in “USB” is so that devices communicate in a standardized way through a standardized bus. The port itself doesn’t need to be universal—after all, USB-C is I believe the first time that the host port and the device port are the same, previously there was always an A for host and B for device, even with mini-USB and micro-USB.
They did make USB-A cables that had a universal (up and down) connector near the end. Got one with my JBL Flip. There is a middle piece that moves to one side or the other depending on how you plug it in.
What are those benefits? The only potential one I have direct experience with (besides speed) is that the connector is reversible, but even that's small-time and a flat out objective downgrade compared to the circular connectors of the 90s, which could be plugged in regardless of orientation.
IIUC USB-C puts less mechanical stress on the port and more on the cable connector, so instead of the port breaking the cable should break.
Circular connectors wouldn't be backwards-compatible either, and would be much harder to manufacture at the size of USB-C. I actually can't think of circular connectors with more than 2 data channels that can be plugged in in any rotation - do you have an example? All the ones I can think of (PS/2, XLR) have a set orientation.