Won’t that cause the fonts to download again if they were loaded by Google fonts? I thought the reason to use something like Google fonts was to have the fonts download only once.
That hasn’t worked for a while. Browsers will NOT use cached resources loaded for foo.com when loading bar.com, even if they are the same resource from the same CDN.
Web fonts are pretty small and only load if used, and loaded only if they're not cached. It's definitely added requests, but those can be deferred intelligently.
Reflowing is preventable using modern techniques, but honestly it doesn't seem like that big of a deal. The tradeoff is you get access to lots of different type options. More type options means more you can convey with type, which is a good thing for people who need to communicate on the web. It's more than just marketing sometimes.
[0]: https://github.com/fontsource/fontsource