Very true. Using a USB 2.0 A-plug cable will work in any USB 3.0 A-socket. B-plugs/sockets and Micro-A/B plugs/sockets are reserved for device side input, but the other end is typically a 3.0 A-plug/socket to attach to a computer. A 2.0 B-plug could technically fit into a 3.0 B-socket, but unless the device itself has backwards compatibility it wouldn't work. Actually, I don't think I've even seen a 3.0 B plug/socket on any devices in person yet, but I have seen a few Micro B on external drives.
*Edit* Also, 2.0 Micro plugs will fit into a 3.0 Micro socket and so long as the device supports it (which it should) it will revert to 2.0 speeds but still function properly.
Edited by modulor - Today at 9:27 am