If POW tokens do become useful, and especially if they become money,
machines will no longer sit idle. Users will expect their computers to
be earning them money (assuming the reward is greater than the cost to
operate). A computer whose earnings are being stolen by a botnet will
be more noticeable to its owner than is the case today, hence we might
expect that in that world, users will work harder to maintain their
computers and clean them of botnet infestations.

Countermeasures by botnet operators would include moderating their take,
perhaps only stealing 10% of the productive capacity of invaded computers,
so that their owners would be unlikely to notice. This kind of thinking
quickly degenerates into unreliable speculation, but it points out the
difficulties of analyzing the full ramifications of a world where POW
tokens are valuble.

Hal Finney
https://www.metzdowd.com/pipermail/cryptography/2009-January.txt