Python virtual environments, particularly using the virtualenv tool, offer developers a way to manage dependencies for multiple projects by creating isolated environments that prevent conflicts and ensure that each project has its own set of dependencies. This isolation is crucial for avoiding issues that arise when different projects require different versions of the same library or even different versions of Python itself. With virtualenv, developers can easily create, activate, and deactivate virtual environments, install packages without affecting the global Python installation, and maintain project consistency by using a requirements.txt file to track dependencies. Despite its benefits, virtualenv has limitations, such as not handling system-level dependencies or guaranteeing reproducibility across different platforms. To address these shortcomings, especially in CI/CD pipelines, the article suggests using Earthly, a CI/CD framework that manages both Python and system-level dependencies through containerization, ensuring consistent and reproducible environments across diverse systems.