If they get enough pre-orders, they'll upgrade the book to hardcover.
From the announcement:
This project has been hammered into its final form and is now print ready. But like many projects around here of late, the sheer idea of releasing it in the standard softcover perfect bound format is just not good enough. So we've set a goal, much like Free City of Eskadia, we are aiming to raise $4000.00 in pre-order money to print this book in hardback.
If we can get $4000.00 in pre-orders for Bluffside: City on the Edge, we'll print this as a hardback. If not, we'll proceed apace and do it as a softcover. Your pledge for the printed book is good either way.
The good news is that the book is PRINT READY. That means if you join us and pre-order today you'll receive a digital copy (assuming you order one) within 72 hours of the order (counting for weekends!). So you can plunge into the City by the Sea immediately! As soon as we hit the funding goal, we send it to print.