I watched half of the movie "Money as Debt" that has been mentioned in this forum a few times.
The movie says that money is created when somebody signs a loan.  The banks create the money for the loan out of thin air.
This seems perfectly reasonable to me.  First of all, a house is not exactly "thin air".  The bankers create money out of houses.  The money supply matches the value of tangible goods that are in the money market.  I admit that I didn't follow all the details, especially the ones that indicate that the interbank loans multiply the money supply many times, but I'm just commenting on this one idea of creating money in exchange for tangible goods.

If I put my house on mortgage for $100k, there is $100k of money created to represent the value of the house that I just put in the money market.  I put goods in the market => there is corresponding amount of money created to represent these goods.  If another person mortgages an identical house, they will get the same amount of $ for it (which will also be created).  If the value of goods that are in the money market doubles, the money supply will also double so that prices will remain constant (excluding a small amount of inflation).

Contrast this with the fixed-money supply of bitcoin:  If I put my house in the market for 1000 bitcoins, I'm reducing the bitcoin supply by 1000 bitcoins.  Bitcoins get scarcer and their value relative to goods (my house) increases.  The next person who mortgages an identical house for bitcoins will receive fewer bitcoins than I did.  We both put in the same amount of goods but we get different amounts of bitcoin, depending on who made the transaction first.  Does this seem a fair exchange system?

The value of 1 bitcoin increases as people use bitcoins more.  The people who hold bitcoins get richer (on paper at least) by holding on to their bitcoins and doing nothing at all.

Which of the two systems seems like a bigger scam?