Sufficient for rapid prototyping
Almost a decade ago, I worked for a company that made, among other things, control panels. We were making a new all-plastic control panel. Rapid Prototyping machines (i.e. 3D printers) were still in their infancy and a prototype panel made by a company with one would cost us over $1000 and take about 4 hours to make. It would have a resolution of about 1.7mm. We got the prototype in, took some fine grade sand paper and a couple of fine-toothed files to it and installed our circuit boards. And that is how we discovered a fatal flaw in the over-all design. Just because they make buttons 5mm wide, does not mean you can place them side by side and expect an average human to use them. It seems obvious now, but the buttons didn't seem that small when we held them in our hands as single components.
A week later, we had a new set of circuit boards and a new prototype enclosure. And that allowed us to have a look at our new control panel and to try it out in the lab under more or less real conditions before we had a mold cast and went into production.
So 1.7mm resolution is just fine for prototyping certain projects. And I would remind people that before they were called "3D printers", they were called "Rapid Prototyping Machines". Keep that in mind. They produce prototypes, not finished goods (yet).
