One of the creators here.
94% of browsers now support [1] the CSS Flexible Box Layout Module Level 1 (Flexbox for short), yet only 3% of all sites use this new technology [2]. We decided to create a visual UI around flexbox to mimic the Illustrator/Sketch alignment and distribution tools, and hopefully get this into the hands of a lot more people - even those who don't write code.
Best of all, we no longer need entire blog posts on how to vertically center something in CSS :)
For some ideas how this can be applied in real-world scenarios, you can see some practical layouts and video tutorials on how to reproduce them here: https://flexbox.webflow.com/
[1] http://caniuse.com/#search=flexbox
[2] https://developer.microsoft.com/en-us/microsoft-edge/platfor...
