Because this article isn't about authoring normal maps, it's strictly focused on the correct settings for export.

Having flat normals like you would get from average weighted normals can improve the quality of normals on those flat surfaces, but it would still leave significant issues on the rounded sections between. So just that alone isn't a solution. There are also issues with using hard edges or mirrored smooth seams and other issues not covered by this article. Because I consider all of those aspects of authoring, for which there are many articles that cover that.