This sounds sensible, as long as the library is geared towards the local Māori community.

And, really. The underlying idea of the Dewey Decimal System is solid: have only a few top level categories, but subdivide and number them recursively. However you don’t need to stick to the exact same categories as Dewey did. It’s often good to deviate from them - because those categories depend a lot on the relevance and association between topics, and both things are situational and culturally dependent. Cue to the example - I see no connection between gardening and conflict resolution, but the Māori people clearly do, so if the library is for them it’s sensible it groups both things together.

Under the Dewey Decimal System, books on wood carving and river systems would not be placed together, nor would books on conflict resolution and gardening.

It’s almost like they’d be placed with books on related topics instead. This Maori traditional system is… not good. Imagine a system where the books are sorted by which Catholic patron saint they fall under, or which greek god they best represent. The librarians even admit in the article that it’s only practical if you’re already well aware of Maori mythos, everyone else gets ‘an opportunity to learn’ (i.e. be completely lost).