We can only automate Regression Tests. Acceptance Tests are the part of Regression Tests.
1. BAT. Build Acceptance Test = P1 use cases + in conjunction with any new feature acceptance automation in upcoming releases.
2. Regression Tests = PAT. Product Acceptance Test (BAT + P2, P3 & P4 use cases)
We can understand that all of the test scenarios (1) are considered “key” to the functioning of the product workflows and all of these product workflow test cases are key to Acceptance of the product for release. Purely as Regression Tests (2), the testers branch off from each of the Product Work Flow scenarios to perform more focused feature by feature testing for (1).