Only 8% of the world’s currency exists as physical cash. The rest of the
money exists electronically. This is because most countries use kind is called
Fiat Money, which means that the currency is just a representation of value.
For example, a
person sending money to someone via bank wire with no physical bill versus
giving the actual money to someone has no difference. It’s just a different way
of transmitting information about money and placing that amount from one person
to another. There is actually nothing valuable about the paper that has the
amount printed on. On the other hand,
sending money equivalent to the value of gold is an actual transfer of a
valuable good.
Once countries decided not to trade money in gold or precious metals, the
need for physical bills diminished, and in the future, money will only become
more and more digital.
Source
Source