Part of the reason it’s important is that mortality statistics are the backbone of public health.

Without knowing how the members of a population die, and at what ages, epidemiologists can only guess how many deaths are potentially preventable. On the other hand, good mortality data can identify overlooked problems and help public health agencies decide where to direct effort and money…

Many physicians find the task even harder when a very old person declines over a few weeks or months and then dies. The steps of that process often include muscular weakness that leads to inactivity and increased susceptibility to infection, or poor intake of food and fluid that leads to dehydration and electrolyte imbalances in the blood and a final fatal heart rhythm. The “underlying cause” is hard to find even with an autopsy.