Having a stick with exposed contacts and no USB shell (like the yubikey has) is not possible in USB3 format. It requires springs on the stick itself, no chance of the easy, pretty much unbreakable yubikey format. That only works for USB2. USB3-A (and -C) reversed the part that is springy, what was previously in the receptacle is now in the plug. Of course USB3-A is a mixed standard so the USB2 part is still as it was for backwards compatibility.
The reason is that the springs wear the most. This ensures longevity of USB ports in laptops where they are hard to replace. A USB cable or device is usually much easier to replace, and also a PC is normally used with many devices so the wear is shared between them now. But it does mean the contacts on the plug side are more fragile now.
And without USB3, filling something at current capacity levels is going to be tedious.
Of course for a yubikey that just transfers a few bytes this is not an issue but for a USB key it is.
Are you thinking of the USB A yubikeys? The 5c that I linked has a shell around the connector. It seems no different to me than any usb type c or thunderbolt cables that I own.
Yes the A yubikeys indeed. That's the original yubikey, the C version came much later. And it's still pretty rare at our work so I didn't imagine the poster referred to that. Also because the A version is much more solid. The connector is just a plate and there's nowhere for dust and dirt to accumulate, unlike the C version.
The reason is that the springs wear the most. This ensures longevity of USB ports in laptops where they are hard to replace. A USB cable or device is usually much easier to replace, and also a PC is normally used with many devices so the wear is shared between them now. But it does mean the contacts on the plug side are more fragile now.
And without USB3, filling something at current capacity levels is going to be tedious.
Of course for a yubikey that just transfers a few bytes this is not an issue but for a USB key it is.