Buying it solely for the Frank Miller bonus content.
"Commentary by Frank Miller. Creating a Masterpiece: The Dark Knight Returns." And "Experience Batman: The Dark Knight Returns Parts 1 & 2 as one seamless epic film." That's what hooked me to this Deluxe Edition. Also there's "Cast/Crew Commentaries" and "Making of Featurettes" (except those are probably on the Blu-ray only, folks, not on the Two-Disc DVD set). Even though I already bought Part 1 and Part 2 separately. I enjoy it enough to get this Deluxe Edition.
I want it.

t:
This coupled with a soundtrack release is a very exciting prospect. I'm actually surprised WB have gone to these lengths. Where the two individual blu-rays big sellers for them?
Compared to the other DC animated movies:
Batman: Mask of the Phantasm made $5,617,391 in theaters.
Batman & Mr. Freeze: SubZero? I've found no sales data.
The Batman/Superman Movie? I've found no sales data.
Batman Beyond: The Movie? I've found no sales data.
Batman Beyond: Return of the Joker? I've found no sales data.
Batman: Mystery of the Batwoman? I've found no sales data.
The Batman vs. Dracula? I've found no sales data.
Superman: Doomsday sold $9,455,120.
Justice League: The New Frontier sold $5,242,952.
Batman: Gotham Knight sold $8,072,890.
Wonder Woman sold $7,561,719.
Green Lantern: First Flight sold $6,260,099.
Superman/Batman: Public Enemies sold $8,470,749.
Justice League: Crisis on Two Earths sold $5,405,463.
Batman: Under the Red Hood sold $7,131,753.
Superman/Batman: Apocalypse sold $6,309,241.
DC Showcase Original Shorts Collection sold $4,034,257.
All-Star Superman sold $4,660,716.
Green Lantern: Emerald Knights sold $2,741,247.
Batman: Year One sold $2,763,042.
Justice League: Doom sold $4,073,754.
Superman vs. The Elite sold $1,279,222.
Batman: The Dark Knight Returns Part 1 sold $2,650,510.
Batman: The Dark Knight Returns Part 2 sold $1,467,026.
Superman: Unbound sold $1,000,984.