Until someone writes custom firmware for Bitaxe to PoW amp their spam.
Discussion
if spammers want to PoW their spam, good for them!
because that's kind of the point:
now they needs to invest in real-world real sources to sustain their load, so they have to carefully calculate how far they're willing to go with their spam.
and relays can always set a PoW limit that is high enough.
but I don't think BitAxes will be useful here!
fun fact I learned from skot9000:
Bitcoin mining ASICs can only calculate sha256d hashes for 80 byte preimages.
maybe a skillful hacker could make something work with severe limitations on note size, but I'm actually quite curious to see a potential economy of nostr note mining around GPUs 🎮⚙️
Assuming they fan get it to work on a relay with some merkle-magic, the spammers would have many order of magnitude more PoW than real mobile users.
If it's just GPU then we'll probably be fine, because phones have those too. It'll just get a bit hot when you post.