The Flat design trend is still going strong. While initially made famous by Windows' Metro design philosophy, it continued via iOS7's new interface and it seems developers really have taken to it as well.
Bootflat is nothing more than a modified and enhanced version of Bootstrap to adhere to this flat design trend and help developers produce flat-based UIs with ease.
Bootflat's advantages are the same as using Bootstrap or any other UI framework, providing a wide range of features and ready-made components that work out of the box, are easy to customize and have proper, professional cross-browser and cross-platform support.
As the original Bootstrap framework, Bootflat comes packed with lots of these ready-made components and also includes support for responsive layouts and mobile devices.
There are also two different styles included with Bootflat, one for elements with rounded corners and one for UI elements with square corners.
There's no reason to use Bootstrap for your flat designs when a specialized tool like Bootflat exists.
Here are some key features of "Bootflat":