Ok, I understand what you're getting at... but they are trying to make (or STRONGLY suggest) people purchase optional components for a game they don't own and have never played... in order to give their product a chance to be marketed to said people. Personally I just feel the implementation is all wrong. The point of the store demoing the game is that they are carrying GW and want you to purchase it from them, if the demo goes well and it's a fun game... they will get their money in on the spot purchases of the game.
The other reason I don't like this setup is that those cards are worthless to me if I decide not to purchase the game... or if I discover I really don't like GW and it'smoney I could've still spent in the store... on something I actually could use or want. In the end I am now much more likely to just wait for a couple of reviews on the game and buy it online (or not) than to spend money on stuff, I may or may not have a use for, in order to demo the game.
Let's assume a pack is somewhere around $3.
$3 won't buy you a decent cup of coffee in a lot of places.
Being out that much to test out a new game? Trivial. If you don't like it, you say to yourself, "Well, I learned something useful today, and I'm only out $3." That's a win.
Then you ask if anyone at the table intends to actually buy the game, and would they like your cards.
You get an afternoon's diversion that taught you not to purchase an expensive game, and some other lucky soul gets an extra pack of cards. Congratulations, Karma +1 and you killed an afternoon for $3, maybe $6. Heck, I live pretty cheaply, but I can't think of much of anything I can do with an afternoon out that doesn't cost
at least that much.
My god, fairly casual hobbyists along the gadget-y end of the spectrum spend $300 to "try something out" and often laugh their asses off if the item in question crashes, blows up, or melts. But PnP "hobbyists" can't even contemplate floating a couple packs of cards to try out a game?
No wonder WotC feels the need to broaden the customer base.