CoH 2 - The Western Front Armies: Oberkommando West

Yep.
I got my cards.

Yes it does give you cards (even the demo gives them) due to the way the game is setup, basically the whole game is considered DLC, everything including the base game is a separate entry under the dlc tab.

About your second question; it unlocks the OKW faction for use in skirmishes and MP games, which is kinda pointless for the former since you can only play skirmishes vs the same faction if you're playing against the AI and due to the way the game is balanced that'll get boring fast.
I'm kinda surprised they only bundled the OKW faction tbh, even the demo keys alienware arena handed out a while back gave you 2 factions to use in MP/skirmish battles, it's what got me hooked on the game in the first place.