Fear of death is useful when you're doing something risky and need to get out of that situation. For instance attempting to climb something that can't be safely climbed. But that's a short term stress response, like the fight/flight/fawn/freeze response; short term, fear is a superpower... or a tool of oppression. But long term it is different (though still a tool of oppression).
Medieval horror mongering to put the fear of hell into people is not helpful and thankfully I've escaped from religion.
However, it's quite likely that when I do die, it will be bloody awful. It's not the death, it's the dying. And the people I care about left behind. And the work left undone.
It's partly linked with the question of calibrating your own selfishness. How much does my survival matter, in various senses, versus my values? Again that's mostly a matter of desperation. For example, if running out of money is a long way off, I can afford to be picky about jobs - even though a longer stretch of unemployment is bad in the long term. So it's another form of procrastination - but it can get mixed up with values.
I disagree about grief though. I have certainly experienced grief, in various forms, for people, though not always people.