I would think the main benefit from this point would be in the future.

If folks have a lot of money stashed away in their house, tax free - and they dont' turn it in, that money is lost. Moving forward, it will be more difficult to do the same sort of thing (in theory) because of the sheer inconvenience of storing up all of those small bills. And if the people do, in fact, wind up being more upfront about their monies, it'll mean more tax revenue for the government - you know, for all the stuff governments want to do. Roads and security and improvements and such.

Basically, this is a push for a better future, with some inconveniences and unfortunate stories in the present. There is some hope. Hope is pretty important.

I'm not sure the benefits are so minuscule compared to the costs.