I'm glad I didn't.
This is also useful for anyone who has to deal with government data, particularly macroeconomic data.
For the U.S., much of this data is already in trillions. That's 13-15 digits, and yet for most government data only 2-4 of them are actually significant digits. So, for my purposes, I'll also add a custom format for billions and for trillions.*
I actually had to use this sort of simplification for a group yesterday. I don't want a fence on the Mexican border, but some people do. But, the common complaint is that it would be too expensive: a common price tag is $15,000,000,000. People can't digest this number. So I pointed out that this is $15B and our government budget is around $3,600B ... so that if it's something you really wanted it's just a drop in the bucket.
* We are within a few years of getting some fairly common statistics needing to be denomination in quadrillions (thousands of trillions).
