Once you learn how to use the Accucut, there is not enough fabric waste to matter. If you cover the whole die with fabric you will have lots of waste but I don't know anyone foolish enough to do that just because the demo person does it to save time.
It took me several years to figure out how to get accurate cuts from the Alto Cut 2. I bought it from the vendor at a quilt show and after watching the dvd many times, it was never pointed out that after the first edge straightening cut the bottom of the fabric had to be aligned against the guide if there is any space between the top of the guide and the bottom. I was doubly upset when I went back to the vendor at other quilt shows and asked why my cuts were not accurate and even showed them how I was cutting and not one told me to realign the fabric before cutting my strips. Now my cuts are accurate, no thanks to the reps.