[imtringued]

For there to be a "deposit only" bank, there must also be a "loan only" bank.

If the money just sits there in a bank account and rots for all eternity you get unemployment and deflation.

The solution to this problem has been to loan out money so that someone else invests the money on your behalf. Inflation exists as an incentive to invest your money and since future incomes are greater (thanks to inflation) it is not very difficult for the borrower to pay the loan back plus some.

Investing doesn't make sense if you have deflation. You can just sit on the money and get rich by on the backs of others. A growing unemployment rate is unavoidable. To maintain stability you would somehow have to get rid of all the useless people or make them work for goods instead of money.