Well said, guest recognition/personalization is where it's at -- with a consistent profile across restaurants that have E la Carte installed, people stand to gain from those features and more e.g realtime data on popular menu items ("likes"), dietary information etc. How many times have your browsed through the ginormous menus at cheesecake and didn't know what to order? With E la Carte, I can see myself trying a menu item recommended by a friend who's been to the restaurant before.
The games are social which enhances the dining experience of most people who use E la Carte tablets. And like with any technology, you have the freedom to not use it, or use just a subset of the available features. Some people are happy to split bills, pay for their meals (without having to wait or hand their credit cards to waiters) and have their receipts emailed to them, even if they didn't order through the device.