I don't use pyenv and have multiple python versions installed (and use them via venv per project). If you don't need to designate one as a global/system Python (which I don't), is there any reason to use pyenv?
If your process to install a specific Python version for a project, independent of system Python, is as fast and simple as `pyenv install 3.9.7`; and if you don't work in a team where having `.python-version` file in the project will download, install and set the exact Python version required: you don't need pyenv.