It's not the goal of the project, but I'm sure they are pretty much the only goal of the donation... Or do you think people would donate at all if there weren't any gifts?
And that's exactly the problem. There's a massive mismatch in expectations. People treat it like a store, where it's more like a micro-scale venture capital investment, without the potential for a huge return.
But it's not a donation at all in many cases. Frequently, you give money in exchange for a product, promised at some future time, generally for a discount over the ultimate retail price. That's an investment, with the finished product being the reward, and the risk being the potential failure of the project. Yes, Kickstarter calls them donations, but when people are putting up money in exchange for a promise of being delivered a product, it's hard to believe that's what they really are.
That's not an investment, any more than buying a keyboard or an iPhone dock at the local computer store is an investment. It's an advance downpayment on a product purchase, with no recourse if the seller never delivers you the product, or delivers something that doesn't meet your expectation.
I've donated to several kickstarters without a backer reward. They're usually film or music projects though, where the finished product is available to everyone for free.
I've backed a few projects that I just wanted to exist, or happen. I put $250 toward a documentary project. Sure I'll get a copy as a "reward" but the copies obviously aren't worth $250 to me. I just wanted it to happen.
