The Plugable USBC-DP adapter cable enables DisplayPort displays to be connected to a computer via a USB-C port which supports "DisplayPort Alternate Mode" (Alt Mode) such as the Apple 12" Retina MacBook 2015/2016, the Chromebook Pixel 2015, Dell XPS 2016, Yoga 900, and many upcoming systems based on the Intel Skylake/Alpine Ridge platform.
Alt Mode adapters allow you to add an additional display output easily and inexpensively on supported systems. Since "DisplayPort Alternate Mode" is a direct pipeline to your graphics processor via special functionality introduced in USB 3.1, there is no performance penalty to using the adapter; the attached display should be just as responsive and functional as if it were connected to a video port directly attached to your system's motherboard.