The benefits of writing a separate test suite for your app

Could not agree more. We have done this with my last project and it was immensely helpful. As our team switched from one version of Angular to another, our tests were consistent and able to catch a flaw on the main landing page that had been completed months before. By having tests separate and having a person(s) responsible for testing, it allows developers more time to fix problems.

In addition, we used our tests for many of the same things the author recommended such as running a thousand instances concurrently to load test and using parameterized inputs to test the database indirectly. It lends some incredible abilities to verify over and over the application works.

(I used Selenium and a number of add ons to do this on our web application)