One of the functions of money in an economy is that it's serves as a store of value.
Yea, money is in no doubt a store of value but it is not a good store of value because it loses its value over the time. Not many people will want to store their value in money rather they would like to use money for exchanges of value rather than to store the value.
While money is an asset that can store value, and also Gold and silver for example, acts as store of value.
Gold and other valuable assets are good store of value especially gold because it is in appreciation value over the years. Bitcoin can be a good store of value because it is a hedge against inflation unlike fiat money.