Quote (thundercock @ 25 Aug 2020 02:44)
Old people tend to vote Republican and they would benefit the most from it.
Iirc, some studies show that old and white people have a greater preference for mail voting than younger and less white ones. Which is good for the GOP. But it also increases turnout, which tends to be bad for the GOP. And late arriving mail ballots almost always break heavily Democratic because that's from all the college students who - of course - procrastinated until the last moment. And of course ballot harvesting is a huge boost for Democrats.
In the case of Florida, the coalitions might also have changed in a way that makes mail voting less attractive for the GOP: polling shows Trump's margin over Biden among the elderly to have deteriorated compared with 2016, but his margins among Cubans a lot better this time around.