What I like about this is that it makes it clear that only Jedi Masters could be taught this ability (all the more reason for why Anakin wanted to become a Master), and that it was only allowed for healing kyber crystals. The method he wanted to use it would be against the Jedi teachings at that time. But Rey and Ben are going to create a new generation of Jedi that won’t follow strict guidelines like this.
That’s a pretty plausible explanation, it might end up as my headcanon until proven otherwise.
I wish TROS had done such an reevaluation of the core beliefs and guidelines of the Jedi Order instead of dropping this point after an interesting setup provided by TLJ.