My only fear is that it depends on the "expert" you use, as it seems very difficult to get a fully objective opinion from anyone, as they will have their own views on what is best etc, which may conflict with another "expert", so will leave you with two different views from two different people on the same product, meaning people are none the wiser .
this is exactly the same scenario when you talk to different tuners no two do the same thing so you end up confused but it wont harm learning about oils then make your own decision based on what you have learned