I can't see how this squares with the scalability problems of proof-of-work systems. Given the big problems with these limits currently happening with bitcoin,

I can't see how this squares with the scalability problems of proof-of-work systems. Given the big problems with these limits currently happening with bitcoin, this seems impossible to use in a high bandwidth system. Already bitcoin transactions are shockingly expensive, with the bulk of the cost hidden from the user by the payout of coins to the miners.