Where do you find Alpine-compatible wheels? Many ones uploaded to PyPI aren't, because e.g. both GitHub actions [0] and Azure pipelines [1] don't have Alpine images. Is it reasonable to expect maintainers of small, open-source libraries to write and maintain their own Alpine runners?
I guess if you know your company's workflow depends on Alpine, you can build and cache them yourself. But the wider community doesn't benefit from that.
Besides my own needs, only one other person has requested additional packages, which I was happy to add. Maintenance is minimal, mostly just approving pull requests created by Dependabot.
I've used alpine images for python in production and not run into any of these issues. The key is to know how to use multistage builds to cache layers.
If you know where to find Alpine-compatible wheels, or host your own, Alpine has no build-speed penalty.