I think it was a smart way to do it... they are using Kickstarter to take pre-orders and to encourage small contributions from those who want to support the effort but don’t necessarily need to buy a printer (by buying a t-shirt, a part printed from their machine, etc.)
It might be a good idea, but Kickstarter have recently made it very clear that per-orders aren't why they exist. By accepting these per-order style Kickstarters they risk having people think of it as a store, which is bound to cause frustration when projects are delayed or cancelled and money is lost.
I don't think that Kickstarter has a problem with pre-orders in general; in fact, that's how they make most of their money. Almost all of their projects involve at some level "pay this much and you will get the final product." What they have a problem with is projects that make it look like they are further along than they are, by using photorealistic mockups and selling multiple quantities of items, as if you're just adding them to a shopping cart.
The new rule is: "Offering multiple quantities of a reward is prohibited. Hardware and Product Design projects can only offer rewards in single quantities or a sensible set (some items only make sense as a pair or as a kit of several items, for instance). The development of new products can be especially complex for creators and offering multiple quantities feels premature, and can imply that products are shrink-wrapped and ready to ship."
It explicitly says that you can offer a reward of one of the item in question (or whatever the most useful set of them is). You cannot, however, have all of your reward levels be different quantities of the item.