USB mining is generally not considered profitable for cryptocurrency mining. USB miners are typically devices with very low processing power and energy efficiency, making them ill-suited for the high computational demands of most cryptocurrencies like Bitcoin.

Bitcoin and many other popular cryptocurrencies are mined using specialized hardware known as ASICs (Application-Specific Integrated Circuits), which are designed specifically for the purpose of mining. These ASICs are much more powerful and efficient compared to USB miners or even regular GPUs (Graphics Processing Units) used in gaming computers.

USB miners were more relevant during the early days of cryptocurrency mining when the network difficulty and computational requirements were lower. However, as cryptocurrencies gained popularity and the networks became more secure, the mining difficulty increased significantly, making it extremely difficult for low-power devices like USB miners to compete and generate a meaningful amount of cryptocurrency.