Scoops for your restaurant, bakery, or commercial kitchen are often needed for both front of house and back of house tasks. They can be used for scooping ice, french fries, ingredients, and many other things. It sure beats using your bare hands! It'll keep things a lot more consistent and clean.
There are basically two different types of kitchen scoops: plastic scoops and metal scoops. There's no overlying rule of thumb for when you'd want to use one versus another: they are both foodsafe, so you're not going to have issues there. It usually comes down to a preference and what you're used to using.
There's also flat-bottomed versus round-bottom scoops. The flat bottom scoops will be nice if you want to set them down flat onto your countertop and not have them move around. Rounded could be better if it works better with the stuff you're scooping and if you don't plan to be setting it down on flat surfaces.
Sometimes these are called shovels instead of scoops, because they can move a lot of stuff around. The smaller scoops (around 6 ounce) are best for putting a few cubes of ice into a cocktail. The medium-sized scoops (12 ounce) could be better used for filling pop glasses with ice. And the large-sized scoops (24 ounce) could fill two large glasses with one scoop. Any larger than that, and you're really talking about bulk filling at that point.