Generally, there are two types of teams that develop applications and customizations for the Salesforce Platform, and before Salesforce DX arrived on the scene, the orgs that the two teams used were often different:
Internal Development Team : This team develops applications and customizations for a single Salesforce customer’s org. The team might be in-house, a third-party consultancy, or a mix of the two. The orgs used for development, test, integration, UAT, and staging are typically Developer, Developer Pro, Partial Copy, and Full Copy sandboxes. Metadata components are moved between the orgs using change sets ...
