Yeah he's a stand-up dude. He runs the older NuVinci N171, not made anymore. The N360 that came later can't handle even our engines' modest power, unfortunately. NuVincis are also quite heavy and take expensive fluid that they like to leak out when warm
It can be, depends on the IGH. A used wheel with an IGH might be under $50 while a brand-new hub itself is $100 or more. NuVincis aren't cheap by any means, they have the most "gears", with 64 different ratios. Oftentimes you have to build the wheel around the hub, too. Not hard to put over $300 into a rear wheel.
"Better" is relative. Sure it's cheaper and easily twice as powerful, but it's also wider, heavier, and has a lower rev range. That rev range limits it in versatility with a single-speed drivetrain. If one uses a CVT to get maximum versatility, the bike is no longer easy to pedal. Long-term term revs over 5K RPM also make the stock flywheel a safety liability. If one doesn't want to chatter teeth off the line, one needs lower gearing or a high-end clutch. I had a 79cc once and I sold it and went with a smaller motor instead, I didn't like the width.