Throughout history, many items have been used to exchange value—such as shells, beads, animal skins, and precious metals. In this respect, these items are regarded as "money." Money doesn't have to be the printed currency we are all familiar with—all it needs is to act as a store of value, be recognizable as a unit of account, and be accepted as a medium of exchange.

Bitcoin has value because it can function as a store of value and a unit of exchange. It also demonstrates six key attributes that enable its use in an economy. The definition of value in a currency has changed over centuries from physical attributes to the velocity of its use in an economy.
Bitcoin demonstrates the attributes of a currency, but its primary source of value lies in its restricted supply and increasing demand