I’m glad you liked it, I love your postCSS plugin!
The reasoning behind my ordering is that first we get the properties that affect where and how the element sits on the page, then the properties that affect its size and box properties and finally how it looks.

I’ve never been much of a fan of functional CSS, that article certainly uses it in a way that I agree with more. I tend to use mixins/extends or composes to create functional style blocks then use them on my semantically named styles.

I think with any of these tools, if it works for you and your project and makes managing your css work for you, then go for it!