If someone becomes a God, they start their own reality, their own universe dimensions, et cetera. This "get your own planet" thing is really insulting!
Exalted men create new universes!!
What a deliciously attractive new meme for young Mormons to latch onto and launch a new set of apologetics from.
It really does let you completely escape some of the more confounding internal inconsistencies of Mormon doctrine.
E.g., The King Follett Discourse version of how God came to be God through "Eternal Progression" is irreconcilable with the immutable God of the Book of Mormon. Irreconcilable if you adhere to the tired old notion of the universe.
But hold on a minute... stop the presses... we've got a new meme!
Just put Father God's eternal progression to become an exalted man into a universe that is external to our (Father God's created) universe. So now, God can be understood to have been changeable in the external universe, but unchangeable in this universe.