Relying solely on penetration testing and manual efforts to test the security of your application can be costly and often will not keep up with the pace of software development of a mobile application. The manual activity would slow down the release process and possibly compromise the completeness of your security testing. A common strategy to reduce the impact of security testing on development teams is to shift left with the testing and verification being done through automation as part of the CI/CD process.
By automating your MAST, you get immediate feedback on security issues in your app, you can remediate them very quickly, and make pentesting more efficient and effective with a higher likelihood of a positive outcome. The automation, the timely feedback, and the ability to quickly fix issues results in less disruptions for the development team and reduced schedule impacts.