The technique imparts the flavor of fresh herbs, garlic and the nuttiness of brown butter to the surface of beef, poultry and fish.
Use coarse salt when seasoning with just salt and pepper. Coarse salt is better for seasoning by hand because it’s easier to see and you can feel the grains pass through your fingers.
In my twenty years in the professional kitchen I’ve never seen a recipe for mashed potatoes. It might have been shoved into a cramped office space somewhere but nobody ever broke it out.