They offer the comfort of sneakers with the polished look of flatsCredit: TheStewartofNY/GC ImagesNEED TO KNOWCharlize Theron and Nicole Kidman have both worn ballerina sneakers recently.A PEOPLE editor tested a pair and called them "lightweight" and comfy for wide feet.Shop celeb-inspired styles for summer travel, errands, and more from $40.Heels? Who needs them. Charlize Theron has a supportive, yet equally polished alternative that’s backed b…