If Jim hides $30 under his mattress and he still has $30 there three weeks later, what function has the money fulfilled?

Jim hides $30 under his mattress and he still has $ 30 this is known as storage of value.

the asset which is being saved, and will be used to retrieve or exchange at later time is known as Store value.

Anything which have purchasing power is known as store value

The store money can be exacted afterward as per there requirement.

This is basically done for saving purpose.

In this method, the flow of money does not take place.