Partition table of nand flash and eMMC

Maybe I'm asking a sample and silly question. I want to know why the partition table of nand flash and eMMC is different. For nand, the partition table is simply a string that gets passed to the kernel during the boot process. However, eMMC uses much more complex GPT partition table like PC disk driver. Why? Is the reason eMMC is block device while nand flash is MTD device(neither char nor block device according to [1]).
Can someone explain more details? Thanks!