Why YSK: When you cook meat, any water on the surface must first evaporate before much browning can occur. You want to get as much of a Maillard reaction as possible in the limited cooking time you have before the meat reaches the correct internal temperature. Removing the moisture first means that the heat of the cooking surface isn’t wasted on evaporation and can instead interact with the meat to form the complex sugars and proteins of the Maillard reaction.
For ground beef, the best solution is to make sure you have enough fat to get good browning. People usually say 80/20 ratio, but I like to have 25% fat on my burger patties. As an experiment, try making a patty with lean meat and you will see how much the moisture will evaporate rapidly and take the heat away from the meat, giving you a sad grey meat. With enough fat, it will keep conducting heat into the crust without boiling all the water inside; as a bonus, you get juicy burgers this way.