Thanks for the detailed reply. I see where you are coming from but I for example never head about Fedora Atomic whilst I am familiar with OpenSUSE MicroOS, GUIX, NixOS. I noticed that MicroOS is the server oriented immutable whilst Aeon is the new orientation for Desktop… ANYWAY, all this immutable talk is anyway pointless, because I was talking about general distributions and not a discussion about immutable distros.
On the topic which distro adopted what first, my confusion did stem from by what context. As I tried to make clear with my confusion about fedora not being rolling release. To cut all this talk short here my answer to your question:
The default value of OpenSUSE Tumbleweed is pretty strong because
rolling release
zypper having sane args for regular tasks (install, search etc.)
btrfs as default filesystem
optimal snapper integration which leads into
making a rolling release distro suitable for non-technical people/daily usage without fear of regular updates
But this is just a general recommendation for “distros”. If the requirements get more specific it makes much more sense to make proper recommendations.