FWIW, I was a beta tester for CS2 and the HDR Merge tool got a lot of discussion. Bottom line is it is a tool in the works for Adobe; they simply added it in its current form as a basic functionality in CS2 because they had what you see already developed.
As I understood it, they did this for two reasons, 1) it is a need in certain forms of digital video editing and 2) since they had the basics available they felt it might also whet the appetites of traditional digital imagists -- ostensibly a more functional version of HDR will give them a reason to upgrade to CS3...
Cheers,
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