Why you develop this plugin?

The logic wasn’t SEO, nearly so much as aesthetic. We’ve made for ourselves and delivered for clients a number of site where the fact that a post would only be in one category was essential for the design-thinking and functionality of how it work. So to save us and client the time of educating all contributors to a site of the need to only put it their post in a single category, we’ve just simplified the process by only letting them put it in one.

Thanks for the question.