A direct contrast to On-Ledger Currencies, On-Ledger Currencies term refers to cryptocurrency created on the relevant blockchain. Bitcoin is the best example of an On-Ledger Currency. It must be noted however that all cryptocurrencies distributed in the crypto market are considered On-Ledger in that they exist within a blockchain network and are created specifically for digital wallets.
On-Ledger Currencies are highly different from Off-Ledger Currencies as the latter is basically just money spent by the nation states, like the Euro, the U.S. Dollar, and the Yen, to mention a few. On-Ledger Currencies are only outperformed by the U.S. Dollar, which is seen as the leading international currency.