a blockchain (this is why Hashgraph claim to be "safe")
But I've not read satoshis.place code so I might be wrong and it might be slow enough to be be done on a blockchain
slow? because you have to wait for a block? don't worry. we have 0-conf.
You have to wait ~1sec for 0-conf
Ah yes. If that's too long I understand why a payment channel is preferable in this situation.
