So, why do they really want a mail-in revote in Florida? From Dan Gelber’s blog (Gelber is Minority Leader of the Florida House of Representatives):

The major reason is that the revote, in addition to making sure Florida voters are heard, should also be a party building exercise. Returned ballots (because of address changes) will help us dramatically improve our voter database. If appropriate we could also ask Democrats to voluntarily give us their emails and telephone numbers so we can communicate with them in November and beyond. All this would help us considerably in the general election. If, however, the state oversees the election, Florida Democrats would be footing the bill without getting the attendant advantages the revote offers.