@Oyvavoy I am enjoying our debate 
I think we are, to an extent, talking at cross-purposes. There are two groups of patients, when it comes to death certificates:
- Have had autopsy: cause of death usually established precisely
- Everyone else - educated guess most of the time.
For group 1, using a precise code is helpful for understanding disease and planning health care because it helps epidemiologists know how many people are dying of any given condition.
But for group 2, using a precise code won't do that, because it's a best guess. In fact, by using a precise code when you are just guessing, you will dilute the accurate coding of group 1.
As a statistician, it may give comfort to feel that all deaths have been given a precise code. But, to plan health care, it is much more useful to know that, of each 100 people autopsied, 10 definitely died of heart disease, than to know that, of every 10,000 non-autopsied deaths, doctors guessed that 1,500 were due to heart disease.