I’m not sure if this has been asked already but I couldn’t find any recent data and I seem to remember @dan said this was being worked on.
Is there an official statement about:

The dimensional accurancy of camera acquisition
Simply put, if i draw a square or a hole, do i get +/1%, +/0.5mm or what else?
This is important if one wants to draw some simple parts by hand with a pen and ruler.
From what I’ve see so far, this method is only good enough for artistic designs where, say, a 10% accurancy is still okay. 
The positioning accurancy on the bed using the camera
Similarly, if a design is positioned in a certain point in the bed using the camera view, how accurate will it be in reality?