Methinks people should understand that "oFfIcIaL iSo/eSd" is literally microsoft doing the uupdump download+conversion for you. The content is THE SAME.
You'll find that it is a mistake when you looked into any UUP main esd file, like professional_en-us.esd, and found that there were no boot.wims.
They are provided by the conversion, and the install experience is the exact same as with the official ISOs (which have the uup folder present too).
prove it (as in actual msdn names of the 2004 isos) they'll both be released to the public sometime in May