When modding: creating a new world or just a new cell?

[worik]

When we want to create a new location, our first move is it to create a new cell and connect it with some door to an existing part of Tamriel.

But I could also create a completely new worldspace and use that for my mod.

 

What is the advantage or disadvantage to shift my new location into it's own worldspace instead of adding another cell to an existing worldspace?

Are there some conditions when I MUST or MUST NOT use one or the other?

 

I couldn't find a comparison between both approaches, yet. If someone has a pointer, I'd be happy to read more.

Thank you