Why store something under the hood, anyway? Just curious...
Well, because Chevy didn't provide ample storage compartments within the interior for things like jumper cables, tools, tow straps, or anything you might actually need when you drive long distances (especially when you live in BFE and it snows 6 months out of the year).
Seriously, I've had jumper cables, a long tow strap, and some tools mounted in that extra battery tray for quite some time now without problems. Only thing to be aware of spatially is the electronic controller mounted just to the left and below the tray. You don't want anything to rest on the cooling fins and potentially overheat the unit or cause a fire. Other than that, IMO it's a good space for stuff.