I think he was saying something about it being review or contest copies. If even one person buys a game due to a review, it pays for itself. And contests, well, it's basic psychology -- people are much more likely to see a game they "won" in a favorable light. They're being tricky~ Which is a perfect idea if your longterm plot is a steampunk utopia. Or if you're a secret vampire overlord. One or the other.
Well, yeah, you are right. But still, the whole discussion can be summed up like this: We: We want to give you more money because DoD is awesome. GLG: Hmm... You know, we have these free copies of DoD we can give out. And we all know where that sort of discussion is going to go, don't we?
Call me crazy but if you make a Kickstarter for Clockwork Empire, the $25 - $35 dollar tier you get a free copy of DoD.... . Your advertising your pass project while supporting your current project with of course advertising and funding. Just my very capitalist thoughts.