Maxperson
Morkus from Orkus
For my players, it's about there being a risk of losing the character. They invest in their characters and want to feel like they can lose it all if they screw up or things go very badly for them. Without that risk, they feel like the game is too easy and that reduces their enjoyment.Yeah. Consider - if the point is some kid of verisimilitude, a player's fear the they'll lose their PC isn't a whole lot like a person's fear that they might die, so the resulting behaviors you see as a result are probaby not terribly similar either. Unless, of course, the players recognizes this fact, and takes an effort to role-pay the character's fear separate from their own. However, if they can do that, they can do that without the stimulus that they'll lose their character.
The more common claim seems to be that you want the player to fear character loss, so they "play smart". Real people when fearful don't often become smarter, or more effectively analytical. In a real-world fear response, most people's ability to apply logical reasoning to the situation drops precipitously. "Fear is the mind-killer," to quote Frank Herbert.
The OP in general makes a point that is very consistent with how mammals are best trained. Negative stimuli tend to yield unpredictable responses - smacking a puppy with a rolled-up newspaper is not a good way to housebreak your dog, for example.
Positive stimuli generally work better - the mammal (and this includes humans) far more quickly and reliably recognizes the desired behavior when they are rewarded than when punished. So, rather than punish a player (by killing characters) for poor play, it is likely better to reward players for whatever good play looks like at your table. If you want to promote a kind of play at your table, clickers and treats beat rolled-up newspapers.
Death is rare in my games, but it does happen. Probably 0-2 times a campaign and my campaigns typically last about a year.