Yeah the matting doesn't really serve any real purpose. I was going to get some thick, rubber matting to put down either side of the power rack so absorb some of the impact when deadlifting and stuff. Unfortunately I never got round to it and, with it being quite expensive, I probably won't bother. Thinking about it, the matting does absorb some of the impact actually. It's not totally useless. In fact I might just have 2 strips down either side of the rack but doubled up so it's thicker.
Pro tip: when building, make sure the vertical bars are oriented correctly. I've built my rack twice and each time I made this mistake!