One advantage of using a dynamic language like Python is that you don't necessarily have to update the client code to be able to use new functions. You can just generate the necessary code during runtime after loading the specification from a web API. I believe this is what google does with their gcloud tools (and that's probably also the reason why it sometimes feels slow to react).
Yes, you can probably do this using Node as well, but Python comes installed on a lot of Unix based systems nowadays, as far as I can tell Node does not.
Yeah, absolutely no reason you couldn't do this (quickly) with Node. The only reason I see to use Python over Node here is for a smaller dep tree (sane Node development still requires a lot of dependencies) and some more mature CLI libraries - lots of CLI apps are written in Python.
"have also heard, especially from customers working with Linux, about our XPlat CLI and its poor integration with popular Linux command-line tools as well as difficulties with installing and maintaining the Node environment"
Yep. This. I know it's not cool to point this out and that front-end folks upgrade Node all the time, but installing Node on a "normal" machine inside your average IT environment is a complete pain, whereas you can do pip install azure-cli as a regular user without installing anything else on most Linux distros out of the box.
Also, I've had nothing but trouble with recent Node versions (and I'm a pyenv/rbenv/*env/etc. guy, have multiple runtimes of everything around, etc. - but most people would try once and never try again).
