If something is conductive, electricity can easily travel through it – generally not a good thing in Explosion Hazardous areas. You want very good conductivity in a power cable or an electronic circuit board.
In Ex areas, particularly confined spaces such as tanks and pipes, conductivity is a huge risk. Anything that is electrified and can hold a large static charge, like a metallic ladder, must be grounded. Grounding is the safe escape route for electricity.
This is why Atexor does not use steel magnets, for example. The Atexor Click’n Fix magnets brackets are fully dissipative (anti-static). Atexor also avoids steel frames as a way to re-enforce luminaires, because such solutions are potentially dangerous and require earthing.