you could steelman that some spammer with a GPU will have an order of magnitude better hashrate by cost/compute than could be achieved with normal consumer hardware, which negates the benefit of PoW. i still believe it’s worth it tho 

 IMO even at two orders of magnitude it would still be quite effective. A few sats per post would also achieve the same thing  

 i agree. 

i also think it would be interesting if paying a few sats per post meant getting a PoW provider to mine say 25 work bits for your note, and then you post it, then both are PoW based