[kureikain]

I think the term referrer to cryptography aspect of the currency.

In a blockchain system, you can generate transaction off-chain(as in, no need for internet access), then you signed it with your private key, and send to a node in the chain. The nodes can verifiy/confim using your public key. The wallet address is a result of hashing your public key.

Compare with a digital currency, you most likely need an account and some sort of credential that managed by the company which issues the currency.