They are not meant to slide. They are meant to grip. There are different protectors you can buy for that purpose without the rubber gripper.
We have only used this product indoors but wouldn't see why they wouldn't work outdoors. They are made of plastic and rubber so the weather should hurt them, and they do work great indoors. We replaced the floor protectors that came on the furniture with these. Because we have wooden floors the couch use to move every time you sat down or got up and after a week or two we would have to rearrange our furniture and put it back where it was suppose to be . Since using these we have not had to move the furniture once. We would recommend these to anyone who has wooden floors but have not needed them outdoors.