Unreal Engine vs Unreal Studio

I was tinkering with both the Unreal Engine and Unreal Studio, but technically couldn’t I just do Arch Viz inside Unreal Engine so I don’t have to download Unreal Studio as well?

Unreal Studio is an “offer”.

The products it includes are the Unreal Engine, and the Datasmith plugin (and a few extras).

It is the same version of the Unreal Engine as used by everyone else. The only tangible difference is the Datasmith plugin that gets installed to it, which opens up some additional functionality, such as additional asset importing.