I feel like dealing with SD cards' inevitable demise is more important than armoring them. What good is a stainless SD card that no longer functions after 2 years of use?
Better thermal conductivity and in turn dissipation than plastic does tend to longer lasting flash chips, how much this change means in real world practice though remains to be seen
It's hard to believe that it would have taken 25 years for the many SD card builders out there to figure out that a heat spreader could solve the degradation problems.
Well considering that most of the SD cards I've had always died from foul play or physical destruction of some kind I think that armoring them is not without merit.
Obviously like all solid state media they do wear out over time, and their wear leveling isn't as good as an SSD which has a much more sophisticated controller with much more sophisticated wear leveling management.