Wipe warmers are worth it as you can warm up the baby wipes before you use them on your babies bottom and that is a good thing.
The wipes when cold may make your baby freak out or at least make them cry or feel uncomfortable and when you warm the wipes up using a baby wipe warmer the baby will not have a cold wipe on their bottom.
After buying a baby wipe warmer I was more easily able to change my babies and toddlers diapers as they used to hate the cold wipes.
But when the wipes were warm they didn't mind me wiping their bottom with the wipe warmer.
You can get by without having a wipe warmer as they are not a necessity but in my opinion the wipe warmer is well worth the money.