That's mostly true to you or I , but I think that to somebody who hasn't built a kit, the biggest difference may be instructions.

Without good illustrated instructions (a very rare thing when buying plans), even a pretty straight-foreward build-from-plans project can be a daunting undertaking for someone who hasn't yet built a kit. Some of the parts and how they go together can just be too hard to picture unless you've seen a couple of versions of them before. The instructions (if they're good) provide that mental picture that the new builder needs to be able to get things together right.

In the sense of not having the ability to picture what things are and/or how they must go together, I think that working in the blind is a pretty good metaphor.