Different forces and material properties are all at relatively different levels.

The one I know offhand that will mess with stuff is the square-cube law. If you double the linear dimensions of something, it's twice as big, linearly, but 4 times the surface area and 8 times as heavy. The strength of anything that depends on area (like friction) won't scale at the same rate as anything that depends on mass or volume or anything.

Not to mention I'm sure this thing can only print a few different materials. Unless those are also _all_ of the materials it's made out of, it couldn't even make itself.

But simply making something smaller is not synonymous with it automatically becoming more accurate or capable of achieving higher resolution. If anything, very high precision machines are typically larger in size than the less accurate ones.

But even if you could get a positioning system that small, I'm pretty sure you can't scale resin printing down three orders of magnitude smaller than this printer. Maybe a tiny CNC?

Or more likely they refer to eventually printing the mems devices used in the printer

Being able to make structures this small could maybe make DIY inkjet printers viable, if you can simplify them enough?

The most exciting are the applications nobody has thought of yet

To look at the output they recommend a separate regular microscope