Had a discussion about this with one of the Nushell contributors, I am conflicted about it. I think the idea of it is somewhat amazing but also somewhat horrendous. I think the concept of this is a step in the right direction in terms of evolving the shell into something better than the traditional shell with concepts from more modern shells, but still has a way to go before adoption is more widespread. My 2c.

I did an in-place upgrade of a three-node cluster from 7.4 to 8. Followed the upgrade docs and it worked without a hitch.