I drove to work this morning (12F) without taking my hands off of 9 and 3. Depending on how you count them, there are at least 12 90° turns on my way to work.
Try driving for 2 hours or more at 10-2 or 9-3. Your arms and hands get tired. You need more than just a section of heated wheel. By having a fully heated wheel, I can change my hand positions, keep the cabin temperature lower, saving more energy than heating the whole wheel. And yes, I routinely drive for 2 hours or more at a time in cold weather. My 2 year-old pickup has a fully heated wheel. It is awesome. "Prius" = "To go before." but toyota doesn't even follow other mfr's anymore.
If you're driving more than 10 minutes the heating system has the entire interior at a comfortable level and the heated wheel is no longer needed.