[armchairhacker]

PoW can theoretically scale effectively infinite because it can mine cryptocurrency. Millions of compromised IoT devices hitting your server? Now you have enough money for a faster server.

It doesn’t matter that the challenge must be verified: present multiple challenges, some are verified while others mine crypto.

[Sesse__]

This is called “installing a cryptominer on your web page” and is generally considered illegitimate.

[armchairhacker]

> generally considered illegitimate

But why? Obviously an unjustified cryptominer is bad, like unnecessarily slow JavaScript, but this one has a good purpose and to the user is no different than PoW.