To answer your question, other tools with package registries typically require accounts, increasingly 2FA, often encourage some sort of signing step. Having GitHub's ToS serve as the source of trust really simplifies things for the Homebrew team
while it's lightweight, shipping the kitchen sink (uv) is a no-go
so, it's a venv, with the pinned dependencies installed [0], a random example of how this looks like, here [1]
(specifically for uv; i tried to get `brew update-python-resources` and `homebrew-pypi-poet` working for a "private" package, it didn't really work; so i went ahead and created uvbrew [2] instead to help with the resource generation)
[0]: https://docs.brew.sh/Python-for-Formula-Authors [1]: https://github.com/hynek/homebrew-tap/blob/main/Formula/doc2... [2]: https://github.com/thewisenerd/uvbrew
here's something that i was writing just yesterday:
#!/usr/bin/env bash
PYSTABLE="3.13"
SERVER="..."
PACKAGE="xyz"
VERSION="0.1.3"
exec uv run --python "$PYSTABLE" --with "$SERVER/$PKG-$VERSION.tar.gz" "$PKG" "$@"