It didn’t take months, the time I did it (running Docker on a Pinebook, which was not a great experience). It took a couple of hours to flip some base images away from Alpine, as Debian already has a load of ARM packages built.
Why did you have to switch from Alpine to Debian? Alpine supports ARM quite happily, and it looks like they're shipping Docker images for ARM (and other architectures, too).
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.
Debian in Docker in comparison offer less surprises, but you have to consistently do the right incantations.
Regarding missing binary wheels on ARM: with more ARM laptops in the wild those would eventually become more common.