For those curious, the Elite x3 bottom is plastic (polycarbonate) with non-conductive coating technology (NCVM) using titanium dioxide.
Plastic/NVCM gives more than metal, is better for shock, is lighter and it does not interfere with signal reception (most phone antennas are at the bottom). The Elite x3 is already a hair heavier than an iPhone 6S Plus. Adding weight while reducing it's shock absorption value is not the right way to go.
For people talking about "stainless steel" in a phone, I think you're being ridiculous. Metal would also not have helped with Mil 810 drop test and IP 67 rating. Everyone loved Nokia for using polycarb and that is what this phone uses with the addition of some vacuum plating for flair. No big deal.
Also, in using the phone for a week now there is so far no issues with it, nor have I seen any reported.