It's nuanced, but ultimately it's not necessary and adds complexity for the user. Especially new users.
Discussion
Has anyone written about the nuance that I can read? I'm genuinely curious.
I've been running on the assumption that pow would be implemented by clients and abstracted completely from users.
It could be, but then spammers will just use a GPU. Users would end up having to pay a PoW provider to be able to compete with spammers.
IIRC there was a PoW nip floating around a year ago or so, I think jb55 wrote it, there might be some comments etc on that
And it's a non-starter for mobile users which are increasingly more and more users.
There are simpler and much better solutions that can be applied to this particular problem.