Problem is that lazy loading will introduce a flicker on fast connections or if the font is already in browser's cache since re-rendering of the page takes some

Problem is that lazy loading will introduce a flicker on fast connections or if the font is already in browser's cache since re-rendering of the page takes some amount of time (more content, slower it will be). And if you have multiple pages, this means this will affect even people on slow connections on every page except the first one. So it's not a win-win solution, one side will have more or less degraded experience.