When you have fixed width font and need to size columns appropriately for the data displayed in eg: a table.
My original response was going to be that you don't actually care about "foo".length in that context, either. You care whether one string is larger than the other, i.e. the actual value doesn't matter -- all that matters is that if a string X is longer than string Y, then the length should increase. But mathematically, that's just a precise definition of requiring the string length, so that logic doesn't work out.
If you email me your paypal/venmo/whatever, you can collect the $20, since you were the first to point out monospaced font. I still feel that monospaced fonts are sidestepping the whole point, but I won't be pedantic about it.
(https://news.ycombinator.com/item?id=29303325 points out why this isn't a sensible operation, if you were curious about why I feel inclined not to concede the bet.)
Just for more context, I was thinking data tables: like this.
There are lots to choose from, and I suppose I don't really care about making a perfect choice. I'm mostly just curious what other people donate to.
Re: the data tables, it's tempting to think that you need the string length for that case. But what you really care about is whether the strings start at the same place, and whether the string fits in a column -- both of which are questions best answered by a font subsystem rather than relying on string length.
But the data table case is so common that I agree it fulfills the terms of the bet, in the strictest sense. But e.g. that Competition / Name column will break for various non-English languages if you try to base the formatting on "number of visible characters."
I think you'd find most people donate based on what's touched their lives, e.g. breast cancer research if you lost a loved on to breast cancer.
If you believe climate change is the existential crisis, then that's a good avenue to explore. e.g., https://www.rainforestcoalition.org/
I ended up donating $200 to this kid who lost his finger and then got a staph infection: https://watsi.org/profile/08a347b3594d-savy
And then fulfilled the bet by donating $20 to Watsi.
E.g., most Asian characters & emoji are 2 cell widths in a fixed with font for a single character. The character "e" is 1 byte in UTF-8, "é" is >1. The "family of four" emoji can be up to 11 code points, 41 bytes (in utf-8), and 2 cell widths (still just an emoji) and is, I presume, a single grapheme cluster.