But the point is, a clutch-less shift is dependent on matching the speed of the next gear and no additional torque from the rear wheel into the output shaft.

When this happens, the clutch-less shift works the same as just shifting with the clutch.

The fact is, the clutch is better for consistently doing this going up the box, thus less wear over time,

Since the output shaft is connected to the rear wheel and the rear wheel is actually still spinning at some crazy RPM it almost seems a moot point.

Besides you don't keep the power on with a clutchless shift the idea is you shut the throttle off whilst you shift, ergo no torque to damage the gearbox.

The same would be said if you used the clutch but kept the throttle wide open. You would damage the gearbox just as much if not more. You wouldn't shift with the clutch in throttle wide open, so why would you shift no clutch throttle wide open...