[0]: https://news.ycombinator.com/item?id=33553659 [1]: https://github.com/mona-sans [2]: https://news.ycombinator.com/item?id=33554633
[0]: https://news.ycombinator.com/item?id=33553659 [1]: https://github.com/mona-sans [2]: https://news.ycombinator.com/item?id=33554633
Now, if you're displaying code or a password or similar that needs to be retyped, then yes they need to be differentiated, but that's not what a font like this is meant for -- that's what monospaced code fonts are for.
But no differentiation is needed for a proportional sans-serif font intended for regular written language. An uppercase i with crossbars above and below would be jarringly ugly for many sans-serif fonts, and similarly a hook at the top of a lowercase L may not fit the font's personality at all, depending on how other letterforms are designed. (And trying to differentiate the lowercase L with something more subtle, by making it a smidgen taller or angling the top, usually might as well be invisible at body text size.)
Given how easy it is to prevent this kind of confusion, I don't really understand why you wouldn't want to at least provide a subtle hint and make either the I or l stand about just a little bit.
"Ill-advised llama farm was Ian's folly."
Why select a font with an ambiguous character in hopes that you'll never encounter a situation where it's unclear... and then face a dilemma when it is? Simply select a properly-designed font in the first place, and all use-cases will be served.
So I wouldn't rely on how elementary-schoolers write as a guide for typographic design.
In any case, there is a perfectly good reason to omit the crossbars, which is consistency. They are essentially serifs, and it's totally inconsistent to use serifs for just one out of 52 letterforms and not on the remaining 51.
Putting crossbars on an I is like a bar through a 7, a slash through a zero, or a bar through a Z. It's a hack for enhanced legibility but it's ugly. It's noisy. It's distracting. We do it in handwriting or in monospaced code fonts when required, but not for professional-looking body text. Sometimes the more aesthetically pleasing choice is the best one, which is something "proper design" takes into account.
And no, the crossbars are not serifs, any more than the horizontal line of a capital G is a serif.
Seems surprisingly defensive to not be in favor of a small change that eliminates an entire category of confusion and improves accessibility.
If they were "proper" bars that were an integral part of the letterform, then in a serif font there would be crossbars on the uppercase i that would then have ending serifs themselves, such as you find at the top of a T. But obviously those aren't there.
So yes, they function entirely as serifs, not like bars in other letters.