It is pointless! But not in the way you think. You NEED one. It's just so much fun! I love playing with mine. Plus, this is the slickest tool ever for making circles. It's great for kids and quilters of all ages. No compass "legs" to pull apart, no dangerous, POINTY "sticker" than can cause injury, just a sturdy, bright orange plastic "thingy" (Radius Arm) and a white plastic "turny wheel" (Rotator). It makes circles from about 1/4" diameter all the way up to 10 inches.
Four inch and 10 centimeter rulers are built in. No pencil box or sewing kit should be without one. And you can't beat the price!
You might also be interested in Sensmatic Pencils, the only mechanical pencil with auto-advancing lead.