Where have you heard or read about this USB bitcoin miner? For you to mine Bitcoin, you need an ASIC miner and that's not as little as an USB.
Right here, on this forum maybe?
https://bitcointalk.org/index.php?topic=5355470.0Later, when Bitcoin mining comes to GPUs or FGPAs, ASICs, you can not return to mine bitcoin with CPUs or USBs.
Why not? If the USB miner is using bitmain S9 or s19 chips, what's stopping you from mining?
You need to differentiate between a CPU or GPU which are standalone units and USB which is a standard for connectivity.