The most sense I can get out of Musk’s claim that “money is a database” is that he means that money merely refers to real goods and services, in the same way an entry in a library’s database might note the location of and other identifying information about a particular physical book. Musk’s point is that the database entry is not the book. The database entry helps you obtain the book. Bringing the analogy back to money, money only helps us get items in the market.