-Returns the invesment buy requiring less human power
-It can run tests 24/7
-We can reuse the test scripts
-Automation helps you find bugs in the early stages
of software development,
reducing expenses and working hours to fix these problems as well.
-It is more fun since no repetitive testing
-Also automating test allows to run tests on thousands of 
mobile devices.Testing all of them manually would take forever
In the end you will have a better quality software 
which will be released earlier, with less problems and
you have used less resources.