To find an item on the shelf somewhere when you think you may have already missed it while walking past the section of the aisle it was in requires backtracking up the aisle, with or without cart, unless you want to go to the end of the aisle, travel the entire length of the adjacent aisle, then come back to the aisle you think your item is in, which could turn out to be a complete waste of time.
Greetings from the guy who always walks right past the raisin bread.