However, you're still wondering what this War Assets in For Honor business is all about. Allow us to explain.
How to get War Assets in For Honor and what they do
War Assets tie directly into the War of the Factions concept that's plastered all over the open beta. That's the territory control concept that you see in the game's multiplayer menus. Ubisoft has even written a helpful FAQ about how War Assets fit into War of the Factions.
Essentially, War Assets are given to you for playing multiplayer, even against AI. The amount of War Assets you get depends on how well you played. You can allocate all of these assets into a single territory or equally allocate them to all territories to help your faction. If you don't allocate the assets yourself, the game will do it for you.
Basically, this is a way to help out your faction in the all-encompassing territory control metagame that permeates all of For Honor. Now go out and help out your faction in the war for land!