What is the point of paying 10 gold to rent a room for the night at an inn? I think i did a small quest that involved renting a room once, but other than that it seems like a stupid, useless part of the game. Am i missing something? Is there a reason to rent rooms?

Gives a well-rested bonus without needing to buy a house. Also gives a place to kill time while shops open without using the "wait" command. Also helps for RPers.

maybe i would use it for well rested bonus. What exactly does the well-rested bonus do for me?

The well-rested bonus after you sleep basically helps you level up faster for a time.. you can use this with some of the guardian stones as well, and you can get an even bigger boost.

I use it for roleplaying, when my character stops for the night in a town, i go straight for the inn.

You know you are playing a RPG?
It helps roleplaying.

That's crazy talk!