What is a Convertible Promissory Note?

A convertible promissory note is a debt instrument that converts to equity in the company that issues it when certain conditions are met.
Why do People Use Banknotes and Promissory Notes as Money Today?

People Use Banknotes and Promissory Notes as Money because people believe the banks and UNITED STATES GOVERNMENT when they lie to you
What is the Validity of a Promissory Note?

A promissory note is only valid if it is for a monetary transaction to create money and debt as banks and lenders do or to pay off money or debt with a Credit Agreement Payoff Security Instrument Promissory Note.