As mentioned, it's when you must make sure that you have perfect precision. Money and counting items is one such example. If I am a bank and get audited, if I h

As mentioned, it's when you must make sure that you have perfect precision. Money and counting items is one such example. If I am a bank and get audited, if I have a transaction that has kept rounding up, and creating eg. 1 cent every time. After 10k transactions I will have "created" $100 from nowhere. The auditing firm will not be happy about this.