Version control (VC) is an essential tool for any serious software development project, even if there's only a single developer.
There are two major benefits. First, a version control system keeps a complete history of all files in the project. This makes it easier to reproduce bug reports and serves as a crude backup mechanism: it's easier to recover from deletions or bad changes.
Second, if there are multiple developers working on a project, version control serves as a form of synchronization. With VC, it's much harder for developers to overwrite others' work.