Higher Ratio of Strength to density or weight.
Meaningless, so does an ant
Hardness and durability of diamond is the standard
If the figures are correct, a standard diamond has a compressibility factor of up to 140 GPa.
If this new material is a real thing, it might be able to withstand up to 700 GPa, which puts it in the same neighbourhood as Platinum which has a GPa of 660.