Pretty much only because it's faster and because of Lucky Charm. Thievery on Fane (or any Undead) is pretty useful throughout the game anyway simply for the stealing aspect, so why wouldn't you want it?
Unless you're only opening chests that are deep in a dungeon, it can't be for "RP" reasons and not wanting to steal. It's still stealing even when you take from containers that don't have the red theft icon above them, unless you really believe people are really so charitable that they intentionally leave their food, gold, gems, weapons, armors and spell books in containers for anyone in need to grab.
Last edited by Sanctuary; 07/10/17 01:36 PM.