Monetary usage of goods is typically divided into three main categories: transactions, economic calculation, and savings. In transactions, a good serves as a medium of exchange, enabling trade. For economic calculation and record-keeping, a good serves as a unit of account, providing a standard to measure value. For savings, a good acts as a store of value, preserving wealth over time.
If a particular good is widely or universally used for all of these roles, it is considered 'money.' However, different goods may fulfill one or more of these monetary roles to varying degrees. For example, airline miles, store coupons, or credit card points can be used as mediums of exchange for specific transactions, even stores of value for short amounts of time, while property, gold, or securities are often used for saving over longer periods.
It's important to distinguish savings from investment or speculation. Savings are primarily about retaining value, whereas investment or speculation involves taking on risk with the expectation of earning a return. A good may enhance its 'moneyness' if it increasingly fulfills one or more of these roles in an economic system over time.