Well, to reply to your points:
Yes, while CN technically only saves 1 move on average, it's a
big difference. That 1 move can be the difference between planning cross and planning cross+1. A one move less cross can mean a bunch. Also, have you ever been to a comp? Because in the one I went to, I had 1 person take over 15 and 2 people take 12-15, and I judged all day long.
There's always nerves at a comp, just like in any sport. But the final round of a world championship and a normal comp have WAYYYYYYYYYY different nerve levels, and in world finals it usually comes down to who controlled their nerves better. Just ask
@DGCubes about his Pyraminx win at Nationals a few years ago(not to diss Daniel, he's amazing at pyra and I couldn't come close)