Some critics of the current system see monetary reform as a key way forward. TVP/TZM advocates (or at least some) think it may be a help in the transition to an RBE.
Interest is a problem in the current system. If you've got money, you can lend it at interest. If you haven't, you have to borrow it at interest. Thus it is a mechanism for making the rich richer. Also, the money to pay the interest has to come into the system. In effect it is simply created and lent - at interest. Thus more money is owed than actually exists, and there must be default on debts by definition.
But if someone has a bit of money to spare, it does make sense for them to lend it to someone who needs it. This leads to us asking why they should lend it without interest. Of course the money is no good to them stuffed under the proverbial mattress- the only real use of money is to pay for goods and services. It has no intrinsic value. For this reason, an increase in the amount of money that exists should correspond to an increase in the amount of goods and services available, but that is hard if not impossible to quantity - hence prices (the trade off between supply and demand) are set by markets.
I am still looking around / trying to understand how the true advantages of money (or apparent advantages) can be gained without the disadvantages.