It'll be interesting to see what happens... but somehow the idea of expending huge amounts of computing power mining cryptocurrency for charity looks like an incredibly more wasteful process than just shutting off your machines when they're not in use and donating the difference in your power bill.
To put this in perspective here is some napkin calculations on how much power dogecoin currently uses:
Assuming an average kh/watt of 2.333 [1] and the total network hashrate of 68 GH/s [2] we can see the network uses about 30 Megawatts of electricity. As a comparison Microsoft uses 250 Megawatts to power for their datacenters [3]. So it is wasteful, yes, but who's to say it's any worse than running datacenters so I can play battlefield 4 with my friends on xbox live which also provides no benefit for charity.
This is a really good point, and I hope they come up with a another proof of work algorithm that does something useful like protein folding, or switch to "proof of stake" which is not compute intensive alternative.
It'll be interesting to see what happens... but somehow the idea of expending huge amounts of computing power mining cryptocurrency for charity looks like an incredibly more wasteful process than just shutting off your machines when they're not in use and donating the difference in your power bill.