The usual has a way of becoming reified as well as invisible. Like fish in water, when we are home we do not see our surroundings for what they are, and we come to believe that this is what reality is truly like. We do not question the norm.
Leaving home forces us to look at the environment more critically, and we start to realize that what we thought was natural is merely conventional —it is just what happens habitually in that specific place we call home.
Dharma teachings recommend leaving home, but it need not be taken literally. Leaving home is fundamentally developing a mind that questions the reality of habitual perceptions and recognizes the difference between what is natural and what is merely normal.