Hi,
Don't buy from Steam, buy directly from Laminar Research : X-plane 11 Digital Download, in the top right corner of that page :
http://www.x-plane.com/desktop/buy-it/
It includes the whole world and everything that can be bought through Steam can be bought from the respective developers websites too.
-You will directly support Laminar Research (I'm not part of the team, I'm just a normal user)
-You will receive final and/or beta updates earlier
-You won't have a 5Gb program in between, adding more layers and more possibilities to encounter malfunctions
-You will understand better the structure of the Simulateur, which is always an asset if you want to install addons properly.
-THE website for third party addons is X-plane.org anyway. Starting from there, you can reach almost everything.
Just look for "Steam" on this forum if you want to read more about it.
Welcome to X-plane community :)