`layout python` means that the venv is managed by the layout script in direnv, but when sourcing manually I can create it with uv (or pyenv, because I sometimes need to pin the python version) and then just add the source line.

`layout python` is great when that just works. I have trouble juggling various Python version effectively with direnv's layout script (I _know_ I'm doing something wrong, but I can just set up a virtual env as a one time operation so...)

(I also like sourcing bceause I know _exactly_ what's happening, as I know more about the activation scripts than the layout script direnv provides. But that's just a personal thing)