There will be multiple iterations of the art files. You'll get e-mailed the files as they're done, and get your chance to influence specific art components. All higher reward levels also include this so you can start playing before the game gets shipped, and make comments about specific cards/art.
Maybe you're pooling together to take advantage of cheaper shipping. Maybe you're giving a copy to Auntie Mabel for her birthday. Maybe you'll keep one as a spare for when your copy gets stolen by your jealous ex after they decide they don't want to imagine you playing awesome games anymore.