However, the purpose it serves best is zesting citrus . . . if you’re using citrus in your cooking and tossing out the zest then you’re really missing out on some serious flavor. A lot of the flavor and all of the acid is in the juice of the fruit, but the zest is where all of the citrus oil hides out. It’s important to include these oils because they manifest themselves differently in a dish. They accent different flavor components and simply but dramatically elevate the flavor of whatever you're adding it to.
What makes this fine grater (AKA a Microplane, also the name of the company that makes it) so good at capturing zest is its ability to just scrape the surface of the fruits. Reaping the colorful zest without bringing along the powerfully bitter pith; that white stuff between the meat of the fruit and the skin.
Living in a small apartment I have a serious aversion to anything taking up space without serving multiple uses. If zesting was the only purpose this tool served, I’d probably invest in one anyway because it does this job so well. Fortunately it serves a multitude of other functions in a small package at a decent price. If you don’t have one, I’d consider getting it.