Displayport on the other hand is integrated already on the graphics card so there's proper identification at VBIOS level and output data is sent to monitor during POST. Here's an example of a graphics card with displayport:
Im not saying one is better than the other, clearly both have their advantages but i personally don't have the need to connect six monitors ( not even 3 ) to my computer. If i were to buy a monitor, i would buy a monitor with DisplayPort or better yet, with both interfaces if available!
"DisplayLink USB graphics technology is designed to connect computers and displays using USB asnd Wireless USB, allowing multiple displays to be connected to a single PC."
"DisplayPort is a digital display interface standard put forth by the Video Electronics Standards Association (VESA) since 2006. It defines a new royalty-free, digital audio/video interconnect, intended to be used primarily between a computer and its display monitor, or a computer and a home-theater system."