True that creating a P2P grid is a complex endeavor, but there's the real fact that hypergrid does not have a built in cryptocurrency - steem or graphene based blockchains could be used for trading ingame goods like linden dollars on second life (except decentralized).
Can you use coinpayments ingame?
I would very much love the idea of course.
Not integrated into the game. Maybe coded into objects in the game that would then point to the internet. I have not fully explored this option just yet. But hope to soon. :)