I like the proposal. I would put the command line item at the top of the list as I think that is the most important determinant, and include a line in the Juliaup list for easy updates to Julia.
Prior to using Juliaup, I would manually uninstall Julia from the Apps on my Windows machine and then manually install the new version. Not too onerous but Juliaup is much easier.
I should mention that I occasionally use the terminal on Windows, and when I use Linux I use the terminal much more often.
Reinforcing @sylvaticus comment, I have heard of docker but have no familiarity with it, and even less familiarity with a container.
What I miss in this proposal is what do I do if I want to update Julia. There should be something on the website for that as well. That should be easy to add.