An ePaper system can be created, which would decrease transaction costs as well.
With something like Bitcoin, this is very difficult to pull off. Bitcoin is form-invariant, i.e. can exist in almost any form. Any medium able to store 64 bytes of data can act as a native Bitcoin form. Furthermore, the acceptance of a credit instrument is burdened with counterparty risk and, for banks, the issuance is accompanied by the costs of maintaining reserves, and these need to be shifted over to the users. Neither of these exist when using specie, and they constitute a hurdle that a credit instrument needs to overcome to decrease transaction costs over specie.
Even in the current day economy the instrument that most investment banks create don't have more than 2 parties entering the transaction as long as the two parties are comfortable taking on the credit risk. However the two parties being large financial institutions, they allow the credit risk to cascade further into the economy. Bitcoin is not immune to this effect.
There is a difference between credit and circulation credit, i.e. credit instruments that circulate as media of exchange. The latter, by definition, involves a counterparty risk.