What's the Difference Between a Ledger and a Bitcoin?

In order to have payment actually be discharged in any functional way, you've got to actually transport physical currency. So this private ledger money system goes all the way back to the earliest 20th century where really hand-to-hand currency was not a huge part of commerce by the 1920s into the 1930s. The more that we can reliably communicate at vast speeds and process information, which means computers and computers talking to each other, the more transactions that we can process and settle faster and faster and faster as long as we're using this ledger money system.