While I despise Mugabe for his stupidity and his brutality, this may be an uncharacteristically good idea for him and his tin-pot-to-end-all-tin-pots regime.
If nothing else, it will cut down on the price of printing the scraps of paper due to the fewer zeros, and introducing a new money is an old and well-respected way of combating inflation, which this is really equivalent to.
Of course, what Mugabe is overlooking is that this is only going to be a stop-gap measure that will NOT last long unless someone starts to counteract the roots of the problem.
And what are the chances of Mugabe actually doing that?