So I did the whole procedure and it said:
Additionally you were granted the following items on Steam:
Promo Cards
Obsidian Edition Upgrade DLC Package
It seems like you don't yet own the Pathfinder Adventures game on Steam. Don't worry, whenever you get the game the above-mentioned items will be available to you!
I now have to buy the game on Steam to get access to that content? So it's not like on mobile where the game is free to play and I unlocked the content by buying the bundle?