Currently, when using the normal CSS editing options, the vendor prefixes are added automatically and this is great. The thing is that when using SCSS, vendor prefixes are not auto added and we have to add them manually (or via mixins).
You are right to point this out. The reasons this doesn’t happen automatically with Sass enabled may not be applicable for much longer.
Properties can be prefixed with Sass
The code editor and UI fields can be used interchangeably even with Sass
Sass files can be imported via Packs > Import > CSS stylesheet
There may still be a case for using postCSS and the autoprefixer plugin. I will check how lightweight it is.
These improvements to Sass support will have to wait a while though. I’m currently working on CSS grid and transform properties 🙂