Taking something simple and making it complex and limited, with Angular 2.0.
The developer was having fun with the technology and showing others how it could be done. Let's encourage this type of behavior.
"I created this to see what it's like to create an AngularJS 2.0 application. I've previously experimented creating a Hacker News clone with AngularJS 1 so this was fun to play with."
It's not so much a showcase as a reason to ever never use this in any product, it's obviously unsuitable for displaying even the most simple, static data without taking forever and making FireFox stutter. It's not an isolated situation with this either, other websites like this perform terribly even thought they are written in the hippest language with the most popular libraries on the market.
Of course Angular doesn't make sense for a site like HN but this is just a demonstration of what's possible with a site we're all familiar with.
A real world example of Angular is when you're working with HIPAA complaint applications which depend on 3rd party data storage sites, such as http://TrueVault.com. None of the patient information is stored on the application server. Instead, it makes client side API requests to the TrueVault storage and updates the page with the data.
Yes, Angular doesn't make sense for a majority of the websites in existence but it does work well for certain applications.
Or let's encourage using the right tools for the right applications. Let's encourage speed and simplicity as desirable goals again. Let's not do it the Google Blogger way, let's not create services that take several seconds to display few lines of text. There's a great framework for that, it's called HTML.
Angular is a good tool for web apps that have information stored on 3rd party websites that have to be called via client side API requests.