为什么我应该避免只为整个应用程序使用一个UIViewController

I've been building iOS apps for a few years now. While I'm usually using a Navigation Controller to manage my View Controllers, I'm wandering what would be the impacts of someone building an iOS app using only one UIViewController to manage all it's views. That way, the developer would navigate between it's views by assigning a new view to the only UIViewController.I've been building iOS apps for a few years now