In the game sense there will /always/ be people traveling between settlements, however, I feel like most people would rather stay in the relative safety of hamlets or towns, if not in major cities.
Beyond that, most people who probably travel out and about will have some sort of combat skill, if they don't they probably have $ to hire some.
Exploration is beneficial because the game will not have everything shown/known at the beginning, starting the game simply with everything is kind of boring, the act of finding ruins, and not putting it on a map, because only you know of them, would be thrilling.