It's fun to buy one and use for practice, you know, setting up pools and see the whole thing in action, you should know that even if you see a USB miner today it's going to be very cheap, that's because they are not profitable anymore.

I can still see loads of this miners on aliexpress website till date, good for practice and other things, it's a shame that no new PoW coins what to run on the sha256 algorithm anymore, if not, USB miners will still be a thing today, not for Bitcoin though but other new altcoins.

Forget about these USB miners and try getting an asic miner that's specifically for mining Bitcoin and make sure you have affordable electricity in your city.