The point of towns and the issue of their watered down nature in XIII is that they make the world feel alive and immerse the player better. One of my main complaints about XIII was how I never gave a crap about Cocoon. To me, saving it was something the characters wanted but the game took no steps to make the player want to save the world or to make the player understand why the characters wanted to save it either.

You get the idea that it is home to them but since the game never gives you details on their attachments to the place, Cocoon is simply just a series of uninspiring dungeons. Even worse is the fact that the few times the game actually lets you talk to NPC's their dialogue is as inspiring as an old school 8-bit RPG and even then I feel FFII and III's NPC's were more fun and interesting.

The really annoying thing is how several other RPGs got this right and the quality of towns and NPCs have gone up in some other RPGs. At the end of XIII, I never felt a sense of accomplishment, simply just the relief of knowing I finally finished a game but I had no attachment to its world and thus never cared how the game was going to end. I ended up approaching XIII more as a game than a story cause I gained my parties resolutions halfway through and the rest of the plot had no meaning to me as a player, I was simply just an outsider watching someone else's problem.

This is why you need towns, so the player can actually have a seamless way of getting to know the world beyond boring monologues and reading source book info.