>>16
>What's its awesome property justifying its insanity?
Statistics.
If I round up a thousand values with one decimal place to the nearest integer and sum them, 1/10th of those times will be a five, so you're 100 over the real value. If you round to even, half those go up and half go down, so you get the true value with many nines precision.
This may not seem like a lot, but think about it. Every month, your interest is compounded on your bank account. They round to the nearest penny. Say they have a million accounts, each one gets interest compounded and rounded, 1/10th of the time ends in a five, so if they round up they're overpaying $10,000 a month. That's a big chunk of change to not add up in the books.