Castles were typically located in strategic locations, such as on top of hills or near bodies of water, and were designed for defense. They were often fortified with thick walls, towers, and moats, and could withstand attacks from enemies.
Houses, on the other hand, were more often located in rural areas or towns and were designed for comfort and everyday living. They were typically made of wood or stone and were not as heavily fortified as castles.
Royalty would often use castles as their primary residences during times of war or unrest, when they needed to be protected from potential threats. They might also use castles as temporary residences while traveling or hunting. However, they would also spend time in their houses, especially during times of peace and when they wanted to relax and enjoy the comforts of home.
So, while royalty did indeed live in castles, it is not true to say that they never lived in houses. They used both types of dwellings for different purposes, depending on the circumstances.