When we say that money can be used as a store of value, we mean
a. it can be used to measure the worth of other things.
b. buyers and sellers are both willing to accept its worth.
c. it will keep its worth over time.
d. its worth can be divided into smaller units.

When we're talking about money and are refering to its possible uses as a store of value, we're talking about that buyers as well as sellers are both willing to accept its worth - b. 

All of us share the idea about the usefulness of money as a mediator for value of other things.