I grew up in/with cars which would score 0 (more like -3 to -5) and made it to adulthood, so I have a feeling that these features are not strictly neccesary.

At the same time what if it saves at least one life a year? (same goes for riding with/without helmets)

My father grew up drinking a ton of alcohol and smoking, like his friends. Many of them are dead.

By your logic, we should keep drinking and smoking.