Example with Discord (a website and an electron app): You have to download the desktop app to have stuff like: game activity (show others what game you are playing), global hotkeys for stuff like muting microphone, local Krisp noise cancellation
The Internet Explorer system stuff is still there, the difference is that when it launches as a normal browser, it automatically opens Edge instead of IE. (iirc)
I like it more than the base game, but I would have never played it if it had been a standalone game.
Both the main game and the dlc are amazing.