Cook the bacon in a large, deep skillet over medium-high heat until crisp, about 10 minutes. Drain on a paper towel-lined plate, reserving about 1 tablespoon of the bacon drippings. Crumble the bacon once cool to the touch.
Preheat the oven's broiler and set the oven rack about 6 inches from the heat source.
Heat the reserved bacon drippings in a separate skillet over medium heat. Stir the butter and garlic salt into the bacon drippings; allow the butter to melt completely. Cook the scallops in the butter mixture until there is a light brown coating on each side, about 4 minutes per side. Transfer the scallops to a baking dish. Spoon the butter sauce over the scallops. Drizzle the horseradish sauce over the scallops and sprinkle with the crumbled bacon.
Bake the scallops under the preheated broiler until the sauce begins to bubble, about 1 minute.