Absentee Ballots? Why do I bother voting by mail if it isn't counted?

It seems that everyone has already given up. Prop 19 is losing by about half a million votes but there are supposedly 7 Million Absentee votes to be counted.?

Am I just really confused about the way Absentee Votes work? I feel like voting by Absentee is basically throwing away your vote at this point because it's not factored into who won. Or is it?

Someone who knows allot about absentee ballots please chime in!