So the strongly worded argument is just because on one locale of an unsupported proprietary system, which renders their entire desktop and applications with an abysmal font, you might get your website rendered with an abysmal font?
What if you get a terrible font choice on the standard `font-family: sans-serif`? Should all my visitors have to download 100 KB of external fonts because Microsoft are inept?
Meh, for my personal website, I'll keep using system-ui.
The issue is broader than that. The article's addendum points out that both Bootstrap and GitHub removed system-ui from their font stack, and another comment in this subthread mentions that Bluesky has done the same. In each case there's a link to comments and/or a PR which gives reasons.
Bootstrap later added it back, but in the PR discussion it was pointed out that this is still an issue on Chinese and Korean Windows, at least.
> Meh, for my personal website, I'll keep using system-ui.
Well sure, but in that case you could also use your own personal language that no-one else knows.
What if you get a terrible font choice on the standard `font-family: sans-serif`? Should all my visitors have to download 100 KB of external fonts because Microsoft are inept?
Meh, for my personal website, I'll keep using system-ui.