I already stated the obvious differences. requirements files cannot capture a lot of metadata that is required to reproduce python setup , PDM deals a lot of important stuff in: Dependency Management in easy to edit pyproject.toml file , properly implementing the standard PEP specs 518 and 612 . Plus it automatically creates .venv with all the packages required when `pdm install` . Also it installs and manage the required Python verion in .venv. It also locks the proper package depedencies in pdm.lock file with proper hashes which pipreq or others can't .

With pyproject.toml being the main config file you can also define build script , run scripts like you can do with `npm run dev` , using `pdm run dev` for example. Also you can define all the development tools and their config along with it.

We used PDM , so it streamlines package and depedency, project management and venv config all in one pyproject.toml - and you can generate requirements.txt and pdm.lock which in turn builds your venv , can easily share with team (just one pyproject.toml file to share) .