Yeah, there’s nothing wrong with USB 2.0 cables existing, I’m just saying: that’s less than ideal for a lot more than just PCIE or high res displays. Even if you put a $3 flash drive at the other end, you’re going to cut the transfer speeds in half.
Worse yet, my Pixel 4a (a USB 3+ phone) shipped with a USB 2 charging cable, throttling the speeds at which I can transfer totally legal files I don't want to upload to the cloud or perform internal storage backups through adb push/pull.
USB 2, 3 (or at least the speeds introduced with 3), and 4 are all valid choices for cables.