Babies cry when they're wiped for obvious reasons. Besides the unpleasant feeling of a full diaper, most wipes are pretty chilly. While cold wipes are hardly dangerous, they must be uncomfortable, and the shock of one being swiped across a dirty bum will fully awaken any drowsy baby.
Thankfully, wipes warmers allow you to clean your infant's tush with anti-microbial wipes that are warmed for comfort. They're not very expensive, and while your friends might think it's a needless item for spoiled babies, you'll be grateful for the extra luxury during those middle-of-the-night diaper changes.