Physics modeling is arguably the most important task of computers. That was the original impetus for building them; artillery calculations in WW2.

All engineering modeling uses physics modeling, almost always linear algebra (which involves large summations). Nuclear medicine—physics, weather forecasting—physics, molecular dynamics and computational chemistry—physics.

Physics modeling is the backbone of modern technology, it's why so much research has been done on doing it efficiently and accurately.

We're using general relativity to calculate sattelite orbits - fuck your point of sale system iff our sattelites come crashing down we're gonna have much bigger problems lol.

That doesn't make any sense. As you say, in that case you have to "spread leftovers", but that isn't really any more difficult with floats than integers.

It's better to use integers, sure. But you're waaaay over-blowing the downsides of floats here. For 99% of uses f64 will be perfectly fine. Obviously don't run a stock exchange with them, but think about something like a shopping cart calculation or a personal finance app. Floats would be perfectly fine there.

I fail to see a difference there, 10.0/3 = 3.33333333333 which you round down to 3.33 (or whatever fraction of a cent you are using) as you say for all accounts then have to deal with the leftovers, if you are using a fixed decimal as the article sugests you get the same issue, if you are using integer fractions of a cent, say milicents you get 1000000/3 = 333333 which gives you the exact same rounding error.

This isnt a problem with the representation of numbers its trying to split a quantity into unequal parts using division. (And it should be noted the double is giving the most accurate representation of 10/3 dollars here, and so would be most accurate if this operation was in the middle of a series of calcuations rather than about to be immediately moving money).

As I said before, doubles probably arent the best way to handle money if you are dealing with high volumes of or complex transactions, but they are not the waiting disaster that single floats are and using a double representation then converting to whole cents when you need to actually move real money (like a sale) is fine.