Aside from being low-maintenance and hardy little plants, they also do not contain compounds that are harmful to dogs. You don’t want your dog to get in a habit of eating the leaves or chewing on your plants.
But, if they happen to nibble a leaf or two from a Peperomia, they will be fine. There is always a chance of some discomfort if your dog has a sensitive stomach, but this is not one of the poisonous plants to dogs, so you shouldn’t have to worry.