GitHub Actions has effectively killed the need for external CI/CD tools like Jenkins, Travis CI, or CircleCI for the vast majority of projects. By defining workflows in simple YAML files right next to your code, you can automate everything from running test suites on PRs, building Docker images, to deploying to AWS. The real power of Actions lies in its marketplace ecosystem. Instead of writing complex bash scripts to authenticate with cloud providers or setup Node.js environments, you simply reference a community-maintained Action.
It is deeply integrated into the GitHub UI, making it easy to block merges if tests fail or require manual approvals before a production deployment. While debugging complex workflows can occasionally feel like playing "YAML roulette" due to the slow feedback loop of pushing commits to trigger runs, tools like `act` (for running workflows locally) help mitigate this. It provides generous free minutes for public repositories.