It all depends on where you set the changes.
I'm really pulling all this from my head (nothing definite, just an educated guess) but changing your settings to "RoW" or other countries will define what your car will do in certain situations.
For example, maybe in other countries, they do not require a chime when you open the door with the lights still on when key is out of the ignition. But North America does so changing it to RoW will disable this chime, while setting it to North America will activate the chime. Another chime would be a seat-belt chime dependent on the country. God forbid someone is retarded enough to drive with a seal-belt.
Sorry, I can't really figure out any other things that might be different.
I've only found that changing it to RoW (in the Instruments settings) MIGHT make your light sensor more sensitive to light changes. That's what I've noticed when I changed it, but it could just be a placebo effect.
Basically, it changes settings depending on the rules and regulations of the country it is set to. That's what I think it does and, honestly, that's probably what it is for.
NOTE: I don't recommend and/or condone doing it though - just in case you get in shit by doing it.