I'm not familiar with client/server stuff. I am familiar with the concept of Portable Programs.
Just like Portable Programs can run locally from the USB, I ask the same about a Portable User...

For example,
by using Easy Context Menu,
https://www.sordum.org/wp-content/uploads/2014/03/easy_context_menu_main.png
Add a program to your right click menu easily (Ec menu) - YouTube

I think...

https://i.snipboard.io/1cOSug.jpg
y

What is expected to be available once logged in to roaming profile, that wouldn't be otherwise?
What benefit is expected such a setup will achieve for us?
...

hsehestedt,
I think the idea of Windows To Go is more close to what I'm asking. There is Portable Windows. There is Portable Program. And I'm asking about the possibility of a Portable User...

Is it theoretically possible?

You install your user profile on your removable disk / smartphone, separately from the rest of the Windows installation. Something like that. The Windows OS resides...