Earlier quoted context omitted.
Three things: ① I believe this only affects macOS, and has no effect on any other platform. ② There’s no such property as font-smoothing. Only -webkit-font-smoothing and -moz-osx-font-smoothing, with their different values. ③ Attempting to control this is highly controversial. You may prefer it one way, but others may prefer it otherwise. See, for example, https://usabilitypost.com/2012/11/05/stop-fixing-font-smooth.…
Ha, you're right about `font-smoothing` - it appears in the OP CSS like this but I guess they meant `font-smooth` [1] (which has a giant red warning akin to what you said). > As a generalisation, you should not do things like this, but leave it to the platform or the user to decide. Tailwind also does it (e.g. see the CSS behind this page [2]). Those guys wrote probably my all-time favourite resource on UI design [3]…
As for Tailwind, speaking bluntly: Tailwind includes some terrible ideas. Just because it supports something, or even because they use it on their own page, doesn’t mean it’s good. (I mean really, just look at that “Applying conditionally” subsection! Changing antialiasing technique on hover or by media query? Have they completely taken leave of their senses!?) Some people like the font-smoothing change. Others loathe it. Overall, changing from normal behaviour is hazardous.