People already mentioned sorting. Another reason is being able to generate various forms automatically: i.e. from "Fstname:William Robert, Lstname:Smith" to ge

People already mentioned sorting. Another reason is being able to generate various forms automatically: i.e. from "Fstname:William Robert, Lstname:Smith" to generate "William Robert Smith", "W.R. Smith", "Bill Smith", or just "Bill" without storing any of these variants separately. Of course this may fail if "William" prefers to be called "Will", not "Bill"...