People can do useful now, it's to use at least one core for mining. Or one low-power graphics card to maintain the network. To reduce the likelihood of an attack before the end of improvements in the code. Of course it is not profitable, but will maintain the security of the network
https://chainz.cryptoid.info/zet/#!extractionhappy to mine ZET with old usb asics found on stortage area this sunmer if a pool is simple already