I think if someone affirms that this alternative toothpaste is better than traditional one with only subjective experience as a proof, this can be dangerous because someone may decide to give up on the standard option and might end up having health issues due to some tip in the nexus.
That being said, if this is just offered as a not-mutually-exclusive option and with a 'do as your own risk' kind of disclaimer, I dont see a problem.
Personally Ive been experimenting with different natural toothpastes, commercially available ones or made by people I know, and its a lot of hit-and-miss at least as far as how clean my teeth feels afterwards. Id like to experiment with some home made recipes, and coconut oil plus other essential oils sound like a good start, though not sure if its enough. What is it about the standard toothpastes that supposedly are good for the teeth? Is it the fluoride? Is it the base? Or some kind of surfactant in the recipe ? Or what? Lets research more, ask dentists, etc.
As for sodium bicarbonate ruinning teeth enammel, I guess we should try to look at scientific publications see if theres any experiment done with that.. Im sure it relates to amounts/dosage of course, considering the commercial toothpaste also often contain some.
Another interesting thing we could research is the teeth health in different native populations, see if there is anywhere where people have good teeth and use some natural alternative.