There is another Thread in here that shows videos of application and which particular spray on bed liner to buy so you don't have a problem. Many folks do this and like it, but it does have the drawback of chipping if you are doing a lot of MDing where your coil bangs against rocks a lot....Of course, that would not be good for your coil anyway!
The advantage is you don't have to take off the cover and clean it sometimes like you do with a standard cover. It's a personal choice.