Wouldn’t it be more parsimonious (in terms of editor time, screen space, etc.) to have scripts as default locale setting, with languages overriding them only where warranted and explicitly set? E.g. scripts would be the default locale, unless editors set a language for a specific alias.
Regardless of the technical solution that is chosen, I still think the documentation should be made more comprehensive and prescriptive.
We have locales, the primary setting, as well as types: with the current UI and documentation, editors might be tempted to conflate some of these fields (as apparent from the discussion in one of the edits I linked above). Plus there are relatively common cases where we don’t have guidance (e.g. the one brought up in this discussion).