I had never thought of using my old, dull rotary cutter blades for paper until hearing about it at a quilting class. I finally bought an inexpensive rotary cutter and marked it "paper" with a Sharpee and use it exclusively for that purpose.
While wrapping Christmas gifts this year it dawned on me to use my paper rotary cutter to cut the wrapping paper. I just wrap my gifts right on top of my large cutting mat, having the paper cutter and a couple of my rulers nearby. It is so much easier than cutting with an old scissors!