Any program that displays at least one number on the screen and you have more of a need to save a few clock cycles then a few bytes. Coming to mind is nearly any thing that displays changing numbers on the screen in real time (or game time) and will be run on a pc with more ram then you are going to use.

Thanks, very cool code, will have to add that to the collection.

Already used it, but I hope to make it use all the 64-bit features so I can save a few bytes
Where can it be used is of course outputting numbers for users. Internally you don't need that, but you really need to show decimals to an average person who reads the outcome. My application was converting statistics to number format: A,5, B,3, etc.
the zeros can be removed by simple compare loop which is penalty-hungry when not taken care of, but can be fast.