I think a better distinction here is mesh vs. solid geometry. This is a tool for creating mesh-based models and has a focus on rendering. STL is a mesh format that you can print with consumer 3D printers and it looks like Vectary supports that as an export format, but it's not a product built for engineering or mechanical design.
That said it looks really cool and I would definitely print something made with it. Trying that out now, actually.