Used a couple of US recipes recently and most of the ingredients are in cups, or spoons, not by weight. This is a nightmare to convert. Do Americans not own scales or something? What's the reason for measuring everything by volume?
If you're baking something that needs exact amounts of certain ingredients, then yeah, a scale is easier. A scale is more accurate, but its slower than using a measured scoop for recipes that don't require more precision than the scoop provides.
You don't actually need the full set. If all you have is 1 tablespoon and 1 cup, it will usually be OK to just eyeball the fractions.