I always feel a bit bad when I exploit bugs in the game, but if it's not a bug and it's just a part of the game that happens to work well for me, I generally have no problem using it. Hidden developer chests, stealing back money after purchases (like with Heralds in Assassin's Creed) and other things that are in the game and just needed to be discovered, I will use and then I laugh thinking about how much easier and faster it is than having to earn it all on my own.