DisplayPort: a better video interface
You could put it this way - DisplayPort has all the capabilities of interfaces like HDMI, but implemented in a better way, without legacy cruft, and with a number of features that take advantage of the DisplayPort's sturdier architecture. As a result of this, DisplayPort isn't just in external monitors, but also laptop internal displays, USB-C port display support, docking stations, and Thunderbolt of all flavors. If you own a display-capable docking station for your laptop, be it classic style multi-pin dock or USB-C, DisplayPort is highly likely to be involved, and even your smartphone might just support DisplayPort over USB-C these days.
Back when I bought my current 144Hz 1440p monitor with G-Sync for my gaming PC, DisplayPort was the only way to hook it all up, since HDMI wasn't yet supported. Ever since, out of a baseless sense of caution, I've always preferred DisplayPort for all my PC video connection needs, and as it turns out - yes, DisplayPort is definitely better than HDMI, and this article will tell you why.