Maybe I heard wrong but supposedly the paragon levels you made during the season will get transfer to non season characters, in theory then since its easier to get to 1-200 than 500-700 it would be better to just do seasons if you want to get a 1k+ paragon level character. I guess its good incentive to someone who wants a real high level paragon character to do seasons then :D.
Season Question Regarding Paragon Levels.