A lot of issues would be solved if multiple such cities covered a state,however if there will be only a few such beautiful cities then expect the crowd coming in all the time and once the momemtum picks up the city will expand. And controlling the crowd can be a nightmare. But it can be achieved. Adding a low carbon footprint methods like solar cookers,urban forests(dont mind the insects) may help also. The concern with such an idea has been scaling up in a sustainable manner,almost every ideal city has ruined because of the population boom