Things should be simple. We believe in testing and so we want to make it as simple as possible...
The main goal for Karma is to bring a productive testing environment to developers. The environment being one where they don't have to set up loads of configurations, but rather a place where developers can just write the code and get instant feedback from their tests. Because getting quick feedback is what makes you productive and creative...
On the AngularJS team, we rely on testing and we always seek better tools to make our life easier.