Its because those touch screens have clunky UI and are slow if they made it simple and straightforward instead of a question for every page it would be as fast if not faster than a person ordering at a register. Most PoS systems are touch screen nowadays so literally all your doing instead of putting in the options in yourself is telling someone else what to put in. They also do it hundreds of times an hour so they are way faster that someone whos only used a kiosk a few times