Why test GUI?

Question

User interface

The value of unit testing logic is clear. TDD works there with a bang and generally saves time.
But I do not understand what is the use of testing graphical interfaces?

Answer 1

Everything where you can make a mistake should be tested. Manually or automatically. Test automation will help detect regressions. Google even bothers with tests that recognize chrome-rendered images.

Answer 2

Interest Ask. No less interesting than: "What happened in your life if you ask such a question."
In fact: