I think Trump is trying to cherry pick the states where mail in voting will help him (not necessarily down ballot) and where it won't. If I recall correctly, he came out some time ago telling people to vote absentee in Florida. I'm not sure that message really got through as he's been ranting about absentee voting almost every day.
Anecdotal info on Pennsylvania.....my cousin lives in rural Pennsylvania and dislikes Trump with a passion. She says she can't admit she's voting for Biden because it's really not safe to do so.........Secret/Hidden Biden voters??