The mask becomes the face

This is exactly what he is proposing, because it is more "useful". But it hardly gives you agency to be someone you are inherently not.

Authenticity is what we lack in the modern world and he is totally fine with that.

We all change with time, whether we want it or not. You can influence that change of your mind and soul, just like you can influence how your body changes.

If you fake being a better person than you are within, then by time you will be given by others more trust, more love, more opportunities. The sands of time will start to erase the old personality and implement the new, which is more reflective of the better environment you're finding yourself in. The good parts of the old you stay, while the bad parts are washed away.

This can be implemented on an industrial scale with military indoctrination, where they can take absolute scum and turn them into honorable soldiers and officers.