If your neighborhood decides for whatever reason that your IOU's are worth what is printed on them or even increasing values over time, then you can generate a lot of cash, and looking from the outside it will look like everyone in the neighborhood is getting filthy rich because all their market caps and transactions sizes will be going through the roof. And you can comfortably say that you have your IOU's backed 1:1 in things of equal value, by just printing 2 everything you hand one out and keeping one, which will naturally be as valuable as the other right? Or you can use one of them to buy BTC/Ether/whatever on your own exchange, whatever, point is that you can keep the value backed in theory because you have a money printing press. This works as long as money is flooding into the system, and there is enough trust in your IOUs.
But what you can't do is try to use IOU printing to guard against the values of your IOU's falling, it just doesn't make sense when Timmy comes by and says "I want my $10k, here's the IOUs" that you say "Ok, wait a second, I have like $20k worth of IOU's I could give you instead, would that make you happy?". Because you aren't proping up the value of the IOU's, your just devaluing them faster.