I find the dimensional merge interesting because we've seen that Chris can't comprehend how big THIS WORLD is. Bob told one of Chris's foreigner girlfriends (Julie or Pandahalo?) something along the lines of
His world seems so much bigger now in letters to Kengle where he doesn't just want Cwcville to merge with Ruckersville, he talks about Gotham overlapping Brooklyn and accurately places Goku and Haruhi Suzumiya in Japan (whereas before he couldn't understand Asia and the classic Sonichu comics assumed Pokémon took place in Virginia), and follows it up by explaining the recombined dimension is a whole universe with Cybertron among other planets. Chris can't wrap his head around things as big as other continents, but he can wrap his head around other planets and infinite universes?
If I had to guess, in Chris's mind the planet Earth is at least as big as the Ohio trip and Japan might be even further away, and other planets might be twice as far and a couple Ohio trips in circumference while universes have several planets of that size from various TV shows.
All of Chris' dimensional merges could fit inside of Asia, or even just Europe, but that's OK, because Chris can't wrap his head around them anyway.