2 things: the platform on the Candies give you a more stable platform if you need to ride unclipped for a section of trail and it also provides a bigger platform in general for those who prefer more support under their feet (for instance, if you don't use a stiff-soled shoe).

Someone riding XC trails might be fine with Eggbeaters and someone riding mostly downhill might want the Candies, but it really is personal preference.