I've never used Blockbuster, but with a resolution of only 854x480 pixels, the DX is not capable of displaying a true HD image, which would have to be at least 1280x720, so I think it's a bit academic. On top of that, a 4.3" screen is way too small for that resolution to be discernible.
If Blockbuster, and the DX permitted sending their HD Blockbuster material via HDMI to an HD capable monitor, which I don't believe it does, it would become relevant.
