You gave an anecdotal example. I can give one too: generally medium density, mixed use, bikeble areas are much safer compared to other options, bc there are always people around, some go to work, some go to shopping, some go to drink a coffee, etc, adn ppl usually feel safer in this areas. On the other hand, low density areas are less safe bc there's no one around to call police if something happens. It's also a health problem both phisical and mental: ppl are more isolated from other ppl, it's harder to meet other ppl, it's much harder when you are old and ppl generally move less bc they must use a car for everything instead of walking/biking to the destination. In low density areas there's also a deficit of 3'rd places to meet ppl