If you do not have a lot of technical knowledge, this might not seem impressive. But these kinds of aviation designs used to be really difficult and expensive to design and prototype. Things used to take months and years are being done in weeks or days, and for costs that are two orders of magnitude lower. And they are just getting started. The technology is advancing rapidly, and lots of impressive things are coming our way. And in addition to those impressive things, a lot of ordinary things will get cheaper and better as rapid prototyping enables better design.
At this point in a blog post, many tech enthusiasts might start talking about how we will all have 3D printers in our house and never have to buy anything from a store. This is silly. No matter what level of technology you have, there will be a lot of production processes that benefit from economies of scale. Sure, there may be a day in the future when I have a 'replicator' that can make things cheaper than a factory can make them today. But the factories of the future will also have access to advanced technology, and they will be full of people who can use that technology more effectively than I can. It will be even cheaper to pick up things at the store.
A comparison to 2D printers is useful. If I wanted to, I could print a copy of 'War and Peace'. But it would be cheaper to order a used copy online, and I would get a better and more convenient product. However, if I lived 30 years ago and somehow had access to a modern printer, printing that book would be cheaper and easier than buying a copy from a local store or a catalog.
The only reason we would use 3-D printing for everyday goods is if transportation becomes incredibly expensive and if the feedstocks can be made easily from random biomass. But that will probably not happen, because if we could make feedstocks from biomass, we will also be able to make fuel from biomass and transportation would be cheap. This technology will not cause any radical changes in the economic order. It will 'simply' be another driver of economic growth.