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.
Yeah for burgers. I’m cheap and usually just have frozen premade patties, which is why they would be wet.
If they are thawed and very wet then it wouldn’t hurt to dry them. I have also heard that they brown best if you minimize the number of flips, ideally just one flip if you time it correctly.