The only reason - if you want to bet the future of your project on an untested framework, that seen no real world use and is still changing during its RC. Or s

The only reason - if you want to bet the future of your project on an untested framework, that seen no real world use and is still changing during its RC. Or simply put. If they named "Angular 2" by its real name "Some other cool framework name" - you would not use it. (e.g. Polymer 2)