I'm not completely up to date on the NuBits forum, but from what I understand Jordan Lee designed NuNet to have zero counterparty risk and zero reserves. They're trying to create a market for liquidity providers, lots of people that will end up providing their own money for liquidity operations. Again, I'm not completely up to date, so try checking out the forum and make up your own mind. Check Jordan's post here about reserves...

https://discuss.nubits.com/t/regarding-reserves-and-fractional-reserve/1126