This is an easy, fast way of writing your stylesheets without having any problems with browser compatibility issues or other bugs that may come up while testing them against different browsers/devices.
It's not perfect but it works well enough for now! The only downside I've noticed so far (and this seems minor) has been some conflicts when using custom media queries within my website because they can't have multiple @media rules all set at once - sometimes you need two sets if one doesn't work correctly due to conflicting declarations from another style sheet; however there are ways around those limitations by creating alternative selectors like!important which solves most people needs in these situations. As previously stated though, nothing too negative about this tool as its still relatively new compared to similar tools out there such as sass & LESS etc., although their support does seem.