There seems to be a misconception going around that when you play in games with a high mortality rate, the player characters lack depth. I think people overestimate the utility of an extensive backstory and underestimate the growth that happens with accomplishment & experience.

Yes, your first character may die abruptly. Any character may. The character that survives becomes incredibly valuable, and the player who has to keep rerolling has a better understanding of the world and the other characters when they bring a new one in.

It becomes a known thing that people regularly die fighting for this group. A new PC's family may weep at their departing son or daughter, knowing full well that they'll never return the same, if they return at all.

Unlike characters written with enormous in-depth backstories, these characters scarcely contradict the setting. They are born out of player knowledge accumulated through experiencing the world directly.

I've played in highly lethal games as well as less lethal games. Both are valid and rife with potential for compelling characters to evolve through play.

I'm running a highly survivable 5e game where the focus is intrigue and crime, and a LotFP game where people die all the time

It's all about how you choose to run things as well as what the players decide to do with their characters.

As for me, I play cautiously & resourcefully no matter what... Because my characters know they're no good to anyone dead.