This is a helpful rubric for understanding poverty as a condition that is rooted, not in a lack of material 'stuff,' but rather in something much more implicitly personal, and intrinsically spiritual; the relative health our relationship to God, Others, the World, and Ourselves.
This has the benefit of explaining the language and experience of poverty in ways that mere materialism does not. Those who self-identify as 'poor' are more often going to define their poverty in terms of shame, impotence, and disenfranchisement, as opposed to low earning, or a lack of material possessions. Indeed, the identification of oneself as 'poor' comes with its own stigma for precisely those reasons. It also takes the most culturally prominent aspect of what we call poverty (lack of stuff), and frames it in a more holistic way; a broken relationship to stuff (or the world around us).
It has the additional benefit of explaining the unique poverty of meaning and community that is present in many middle-class neighborhoods as (while clearly different) rooted in the same basic state of humanity as the poverty of environment and self that is present in many economically challenged neighborhoods.
Further, it highlights the basic flaw in most attempts to combat poverty, namely through direct redistribution of goods and services. If all forms of poverty are rooted in a lack of spiritual health and/or maturity, and a broken relationship in one or more of these areas, then changing the circumstances of the poor won't alleviate their poverty (a painfully obvious reality in economically challenged communities the world over), but simply exacerbate the problem through the perpetuation of impotence, self-victimization, and manipulation.
Finally, it points to the common solution; a resolute commitment to the process of developing a healthy relationship with God, Others, the World, and Self; namely discipleship unto Christ-likeness within the multicultural community of God's missional people.