The HDMI port on your motherboard or GPU usually connects to your primary monitor. If you're using a relatively new graphics card and monitor, your HDMI port is probably vacant, considering many ...
HDMI excels for media consumption, while PC gamers prefer DisplayPort.
Laptops are practical because you can take them with you. However, laptops have a relatively small screen. If you work on a mobile computer, it quickly becomes annoying to constantly switch programs.