Player Character Death

I gather that some tables have a policy (sometimes explicit) that player characters cannot die. This baffles me.

I get that we become very attached to our characters. Invested in their progress. It should be tragic when a character dies. That said, providing plot armour to characters cheapens them. If you know that a character cannot die then whence comes heroism? Heroes are heroes because they do things others are unwilling, or unable, to do. Principal among these is risking their life for a cause.

It is also important to note that if your character dies in one adventure that is not necessarily the end. Characters can always participate in other adventures, they only “die” in one adventure/campaign.

At my table character death is an ever present risk. I believe this motivates characters to be cautious but it also makes their actions in the face of danger meaningful.