How so? If anything, apk is way nicer than apt in a container build script (or anything automated); with apt you have to use -y and maybe force the noninteractive frontend, where `apk add foo` just works, correctly, automatically, with no effort required.

> Also much easier to set locale.

> considering potentially slower performance:

It's slower at installing python packages from pypi since it can't use cached versions. That's not the same thing as "it's slow".

> Since minimal ubuntu & debian exist, I think the question should be: "Why would you use alpine?"

Because minimal ubuntu is still ~3 times the size of alpine, alpine is much smaller and simpler, alpine defaults to staying small (even if you remember to --no-install-recommends, deb packages are bigger and less modular), and I don't have to remember how to force apt to run in "no really install without asking questions" mode.