Hi,
Centos/ubuntu/debian have such functionality so Nimble/Wmspanel teams don't have to reinvent the wheel. I don't know about Windows/MacOS though.
Any or all packages in the system could be upgraded by package manager even now. Just check how it works.
I'd not recommend to do that though. Even though we try to release new versions without any issue but nobody in SW industry can produce products without any issues. And we too.
When you decide to upgrade you need to pay attention to make sure that your assets work after upgrade. You can upgrade servers after some tests on your side. In case you see something you can rollback to older release. I think we are very far from the moment when products under active development could be upgraded automatically. Human attention still needed IMHO