He's going significantly faster than the other cars, since he doesn't have to slow down to try and maintain traction on the turn

Because he could go pedal to the metal while everyone else was limited in speed to negotiate the turn using only the measly traction from their tires.

The path length is a bit longer, but his speed was so much more that the trade off was worth it.

The other guys aren't limited by power, they're limited by grip. The wall adds lots of friction, sure, but he also now has unlimited grip and therefore full power.

He went about 110 km/h faster than the other cars around that turn, pretty sure he also set a lap record by doing that move. The fact that the finish line comes up right at the end of the turn also likely helped him, as it didn't allow his competitors to gain too much speed between exiting the turn and finishing.