Researchers often stop after reading the files currently visible in a repository. That is enough for many questions, but it can miss the publication context around those files.
Tags and releases are useful because maintainers use them to describe what a version meant at the moment it was published. A release note can reference a migration, a verification record, or an external authority without placing that information in the current source tree.
This matters most when a project intentionally keeps generated or operational material out of the repository itself. The release becomes the bridge between the code and the record maintained somewhere else.
Do not treat old releases as automatically correct. Treat them as dated public statements that can be compared with the current project.