I do not have a Cricut/Vinyl cutter to cut this stuff and would like to play with conductive material. I saw an Instructables where someone zoomed in a PCB design and cut the traces out of copper foil and mounted on glass for a decorative display. Since it is conductive, you can then solder components to it (such as leds) and make the display interactive.
Reflective isn’t so much the issue as the fact that it’s metal. The machine does not have the power to cut metal.
If you search, a handful of people here have worked with PCBs , but to remove etch mask before chemical etching. This is also a common practice “on the web” in general.
It is also the fact that it is copper, which is specifically reflective on the same light wavelength that the GF uses. You should use care when using any copper alloy, and you should not use copper in the GF at all if there is any chance the beam will hit unmasked metal.
Just because we see something is shiny, like mirrored acrylic, doesn’t mean the GF sees it as shiny. Copper has a very high IR reflectivity, where acrylic, even mirrored acrylic, is IR opaque so the GF doesn’t really see any difference between mirrored acrylic and normal.