[rtkwe]

Most people for these aren't buying new equipment for this though so the only real cost is the electricity and a tiny bit of premature wear on components. It'd take a long time of running to have spent enough electricity inefficiently to make up for the cost of the CPU and GPU being used.

It's also way easier to get people to just download and run something rather than donating money, the cash donation is hard and definite while the costs of running a distributed computing client is nebulous.