Ive used these mesh cages before for Veiled Chameleons. Keep in mind these opinions are based on that experinece.
The dont hold heat at all.
Its not very easy to see your animals through the mesh.
If ya have lizards in there crickets can EAT through it. (Found that out the hard way).
It melts easily.
The zippers on each side open easy with some nudging.
Thats just the tip of the iceberg. I can only imagine if you housed a corn in there with aspen bedding thats 1> He'd have no problems opening the zippers, 2> Unless in a heated room he'd freeze & 3> The smaller particles of aspen would keep coming through the 1000's of little holes in the mesh...
Anyway, This sure seems like a rant. Ill stop.