Shoelaces can make a difference on how tight a shoe grips your feet. This counts in ultra since after a certain distance the feet tend to swallow and get bigger during a training day or race. This is not a big deal, but a fact to keep in mind: you shouldn't use shoes that are too tight, or even so, you might need to change them at mid race to have a pair that fits just right.
One of my old shoes had laces placed in an original way so that the width of the foot could have more room at the height of the ball of feet. I should try that kind of lacing again.