Bitcoin represents a form of gold which has transcended physicality and operates within the cyber domain. It’s very possible to send hundreds of millions USD worth of bitcoin within seconds and only the sender and receiver are aware of the identities involved. Physical actors cannot exert control over the portability of this commodity, and therefore, ‘digital gold’ represents bitcoin accurately.
The need for money comes from the idea that we live on a planet with finite resources. Human desire is not limited, yet resources vary by scarcity and availability. Therefore, it is necessary to have a medium to exchange those resources which are not perfectly abundant. A unit of exchange is necessary to allocate resources among a population with theoretically limitless desire.