If you are a programmer who can't do art (most of us), conceiving a product that will be competitive enough to sell (or even generate ad impressions in the flash space), you need budget for an artist (or you need to find a decent one that will work for free)..
I personally find it easier to fire up a 3d modeling tool and knock out low-poly spaceships or simple trees, than to have sat down with paper and pencil and done the same thing (god forbid I try 2D art on the computer, it still looks like I'm 7 and toying around in macpaint).
With modern hardware and commercial/indie/free-licensed engines, the complexity barrier just isn't there between 2D and 3D any longer. I know I could do something like Edelwiss's Ether Vapor (without the character portraits) far more easily than I could do something like RakeInGrass's Jets'n'Guns.
At least I took some music classes in college and can do that bit.