It brings the cost down
by letting us manufacture parts in large batches, without needing to invest lots of money into inventory beforehand. This reduces our financial risk while allowing us to offer products at a lower price.
It helps us gauge the market
to see if our idea is something people actually want. If a project was to fail to reach a funding goal, that would tell us that the interest may not be adequate for the product to be viable anyway.
Our backers provide tons of feedback
both during the campaign and after. For many of our Kickstarter projects, we were able to add new features and options before the 30-day campaign even ended. This way, the product design is driven more directly by what people actually want, rather than just what we originally guess they want.