If I have a $100,000 mortgage on my house, I don't need $100,000 to pay it off. I only need $700 (each month). And while, money is based on debt, it is mostly virtual money created by FRB. The real money (if you can call it that) is the monetary base. Since FRB is possible with Bitcoin, it makes more sense to compare the number of bitcoins to the monetary base (MB or M0), not M1, M2, M3 or M4.