Proof of work is horrific. Means someones old phone has a meltdown trying to load the page while a warehouse in china with the latest GPUs cranks out billions of proofs per second. You could even utilize botnets to get random laptops and fridges to do your PoW.
If this was a mining situation, then yes, it would be dumb.
Is that what this is actually doing though? Is it PoW for a mining operation, or just causing some electrons to be moved around to prove your not a bot? I didn't read too far into what the PoW actually is since their demo shat the bed.
> or just causing some electrons to be moved around to prove your not a bot?
The problem is spam networks have more computers and more power than your phone does so any proof that you can do, spammers can do 1000x faster. PoW can sort of work when your attack to defend against is a ddos situation where an attacker has to make far more requests than the average user, but most captchas try to defend against bots being able to use the site at all which PoW can not do.
how does doing computation without human interaction prove you're not a bot? It only proves you're running a browser with javascript enabled on average hardware.