Testing is one of the most important factors when it comes to application development. Developers do their best to develop a sophisticated application that runs smoothly. But there are always scenarios that developers cannot think of, just because they can only be tested when the application is used with the mindset of an end user.
While developers are working hard to develop the application, it is crucial for the application to be tested with the user in mind, and to test things a developer wouldn't think of.
Testers are there to make sure that the application performs as intended, and that one feature does not affect the other features in an application.
While it is great to have manual testers testing the application, and it does make sure that the application is tested and used as an end user would...