I mean isn't 50% better than the 100% that these crypto miners do? And those miners keep going for as long as you have the page open, not just while scrolling.
What if you could choose a "support level" or unlock features by donating more resources? I'm thinking out loud here, but I've never heard of customer-donated CPU as a business model and there might be something here. For an author trying to monetize content online all of the "normal" options are pretty bad right now. I think most digital entertainment just isn't very valuable these days, but I'll bet the mining thing has some characteristics that compare favorably to both ads and (micro)payments.
Of course, if it was a viable strategy, wouldn't some malware authors write the malware to do this instead of ransoming files? Has that been tried? Is it a thing?
The main problem for legitimate operations is that the user will spend far more on electricity than what the site operator will earn, especially with implementations running in the browser which still aren't yet able to be as performant as you would like. With that in mind a direct exchange of currency for features/access makes a lot more sense unless you want to trick your users. Most won't realize why their power bill is so high.
There are malwares that mine crypto currencies, usually while the machine is idle as to not alert the user that something is up with their machine. However these profits are also quite low since you're using mostly low end machines.
Crypto lockers are of course way more evil, but they function just as well on low quality hardware so I can understand why malware authors do it.
Of course, if it was a viable strategy, wouldn't some malware authors write the malware to do this instead of ransoming files? Has that been tried? Is it a thing?