Let's say I have little interest in Wyrd initially, but get the book and some statcards. I play a game or two, and decide I don't like it. Wyrd lost nothing, as I would not buy the game otherwise anyway. Now, assume I liked the game, but decided to play with whatever proxies...again, Wyrd lost nothing, because I was NOT willing to buy the models in the first place. Now, assume I liked the game, and the aesthetics- I will then buy models, so Wyrd actually gets money from a customer which otherwise would not get into the game.
Essentially, you're not selling to people who would not buy anyway, but you're selling to people who were on the fence.