I don't know I get where you're coming from a graphic design standpoint, but on the user side of it. Rounding up is way worse as it makes you think you have enough for something when you don't. Like if your bank did this when you were going out for lunch the day before your next paycheck. You think you could splurge on something but you can't, you're in line to pay, you've made the order for it and nope bank rounded up.
in this case, yes. But - per your bank example - your bank basically knows that (almost) every number they are every dealing with - at least every number that might need to be formatted - is a currency. So they can apply rules accordingly. Like, because it's currency, your bank is rarely going to - if ever - truncate a number for UI "neatness." Your bank is always going to favor absolute precision in every case. But we use the same rounding and truncation logic for basically everything. Damage, kills, games played, KDR, and currency. And yes, we could "always round down." But does that make as much sense for games played? Or damage? I am less sure. And yes, you can make it like an optional arg - round down/round up - but then you have to think through what's "best" in every case, and then make sure you have test cases for all those things, and ... Well, that's why I had found this be such a whack-a-mole type of debugging process to get right.