Root vs Non Root User when building images

[Nebulised]

Apologies if I have somehow missed the answer to this elsewhere but I can't seem to find one for podman specifically.

When building images using a containerfile, is it still best practice to run as a non root user? E.g. for node npm ci/pythons pip install?

Presumably if so, rather than using userns=keep-id you would instead map it to the non root user created inside?

Does this have security benefits to do it as a non root user, considering root is in fact just your user account anyway outside of the container?

Thanks for your time

[baude]

I guess I look at it inversely; is there any reason to build with privileges? I cant think of anything offhand unless your containerfile needs specific privileges.