Dude, you people are reading entirely too much into it. It's a suspension of disbelief. Many works of fiction utilize them.

Another important thing to keep in mind--and this goes for absolutely every game ever made--is that gameplay is never canon. Why? Because there are a million different outcomes based on every single button or tap of the joystick the player makes. The story is canon, the general plot progression is canon, the mini-stories carried out in some of the more prominent sidequests are canon (but not all of them), FMVs and in-game cutscenes are canon, and the most realistic depictions are canon. But the things that the player carries out him- or herself is not canon, and this includes how one traverses the world map; and, to a certain extent, the world map itself. If the actual world map is the canonical depiction of the world, then the world is mostly barren, the towns cover five of the US' states, and Squall is as tall as Godzilla. The world map is a representation of the characters transitioning from one area to the next, not an actual depiction of it.