Together with higher visibility and "already known procedures", the following is not to be understated:
At least with fixed-amount projects (can't remember what they are really called), the backers can be sure that no money is taken before the alotted/required minimum amount is reached. That in itself is a motivation for a lot of people to just try it – fighting the "nobody want's to be first"-syndrome. Not really relevant for most of us here for this project (most of us would trust chen to do right), but can be huge when trying to get backers outside of TMO.