This would be helpful in determining who got killed by who after a long game when you need to check it fast.
For example during a trial when some evidence is presented. Let's say person A was seen visiting person B night 2 by a detective. And then person B died (got killed by SK).
Now its day 7, the SK is already lynched, and the detective claims that person A is GF because he visited a dead person. (It's been a long game and the detective forgot that B was killed by SK).
Of course you could scroll through the logs to see that A is innocent, but it would take time and most people don't do it.
Being able to hover their mouse over the dead person in the graveyard would show that he had several stab wounds.
tl;dr
Suggestion:
Hovering your mouse over a person in the graveyard would show how he was killed (shot at close range, run over by a bus, stab wounds etc.)