(Also, it’s not clear that a deterministic POW works well for an application like Bitcoin; it might let the owner of the fastest computer win every POW race, giving him too much power.)
Indeed. And don’t forget that through the magic of botnets, the bad guys have vastly more compute power available than the good guys.
You know those crackpot ideas that keep showing up in snake oil crypto? Well, e-postage is snake oil antispam.
R’s, John