They give some examples of differences, but it's not clear (as a non-expert) whether these are necessary in the US/CA, examples of regulatory capture, or irrelevant details.
It's not useful where "standardization" means either writing a document everybody agrees but nobody actually implements, or, the document just says do any of six things but each vendor chooses differently, or worst of all the document says it's basically dealer's choice so in practice the standard was worthless. In these cases the "standard" is just a thin barrier to entry, no real benefit to consumers since they can't swap supplier.
This often means accepting that maybe the global standard isn't quite ideal for you in some sense, but must be enforced anyway.