Useless Culinary Extravagances

I can understand tools like peelers (using a knife to peel is inefficient), zesters (peeling then using a knife to cut peels finely is a bit of a pain), and even melon ballers (the spheres look cool and they're difficult to make with a standard spoon). But mango slicers? Apple splitters? Both of these cut its fruit into six or eight segments at once. Do people really buy these when a simple three or four quick slices with a chefs knife would do the same work? And do the people who buy them actually use them or only buy them to show them off?