Robin Hanson thinks an optimal donation policy looks like saving up and investing as much money as you can and then making a large donation at the end of your life. So retirement accounts seem sensible from this point of view ("tax advantaged" seems like an important keyword here).

Another reason would be to save up money to pass on to your family after you die.

The mortality rate you cite doesn't control for demographics, which I think is important. Many people die early in ways that I think the LW demographic can avoid.