Answer:
Always available to run: You can run the tests 24/7, when you are at work, when you leave the office or if you working remote, you can run the test. They can be run virtually unattended, leaving the results to be monitored towards the end of the process.
Fewer human resources: You can reduce the people advocated on testing, you would need a QA automation to write your scripts to automate your tests, instead of people doing manual tests. In addition, once automated, the test library execution is faster and runs longer than manual testing.
Reusability and reliability: The scripts are reusable, a script could be used hundreds of times before need changes. It allows you to test exactly the same, without forgetting any steps this is why is more reliable and way quicker than manual test where people may cause.
