Low production cost does nothing for the development cost. You will still need design work, internal testing, and art. Playtesting and getting LFL approval costs time, but probably requires a chunk of FFG time (= money) as well.
I'm more interested about the App, whatever it will contain. If it comes with its own missions, getting multi-expansion content for that would be more probable than a physical multi-expansion campaign book.
Yeah, I'm not saying that this is going to take $0 to produce and cost $0. Simply that a pack with tiles, heroes, cards, plastic minis, and campaign missions is going to cost more to make and therefore would cost more to buy than simply a booklet of campaign missions. I don't really see a point in arguing against that...