Paul Turley lays out an explanation:
Back in December, I posted this short article about how Power BI can participate in Continuous Integration & Continuous Deployment (CI/CD), from simplified code sharing and version control all the way up to fully-automated Build automation & deployment scenarios. However, since the product inception, there have been significant challenges in orchestrating versioning and code sharing with a single PBIX file. Achieving DevOps and CI/CD was possible but it required creative work-arounds and manual steps. In April of this year, Nathan Hales contributed this post, showing how to use Tabular Editor to manually decompose a PBIX file into a Model.bim and then create a Git repo and Azure DevOps project.
Although the essential pattern is the same, the need for manual steps and work-arounds is eliminated with this new feature release!
This is really good news, and Paul shows you how to enable the feature (currently in preview) and use it.