I've been playing a lot of Dyson Sphere Program the last few days. The game has a blueprint feature which works similarly to Factorio's. It's made me wonder what such blueprints are for.
One cool thing Factorio supports, and I don't know if DSP does, is exporting the blueprint as text. You can then share the text with someone else. This is one thing blueprints afford: Sharing something you built with someone else. Maybe it is the most efficient or most compact oil processing setup you've come up with. Maybe it's an example of using a weird edge case to speed up your factory. Whatever, doesn't matter, it's for sharing. It's for other people and only through them for the maker.
You can make blueprints for other reasons though, and in Factorio I have a bunch of them. The one that comes to mind right now is a giant bank of furnaces. In my last save I liked to slap it down and watch my construction drones set all the buildings in place. It's satisfying to see the waves of leaving and returning drones and hear the rapid click-click-click of building placements as the blueprint slowly fades in from ghost to placed building. So that's another reason: To direct construction drones.
In Dyson Sphere Program you have construction drones, too, but they're much less spectacular early game. So far I've only got three or five, and anyway the pieces I want to build are rarely on such a scale. Although I do end up building lots of furnaces, and I might want to set up a blueprint for that. DSP's veins are much more intrusive (blocking buildings) and closer together in a way that makes general blueprints less convenient than I remember them being in Factorio. (This also seems to hamper main bus designs, since horizontal space is much more at a premium in DSP than in Factorio.) But maybe I can find a use for blueprints if I try making some.