Let’s discuss the rubber floor protectors. These types of floor protectors as you may have guessed are not used to help slide your furniture. In fact they do quite the opposite. They are very effective in keeping furniture from moving on slick surfaces. They are used for cane tips or crutches to prevent catastrophes on hard marble flooring. You may have a coffee table that you wish would stay in its place, or folding chairs that easily slides from under you. Along with their anti-slip properties, rubber floor protectors are also used in environments where vibrations might be an issue.
You would see these under an air compressor, table saw, etc. Remember that you want to get a floor protector that is proportional to the size and especially weigh of the object it is supporting. You might also need to consider vibration or type of vibration to get the proper footing. A low density rubber will dampen vibrations quite well however it will not be as durable as a high density rubber.
Of course aesthetics is not a major concern in an industrial application however for home use it might be an issue since rubber chair leg covers are rarely in a color that matches your furniture. They are typically found in beige or black color.