Hello Vertnyc

I will try to come with complete answers to your questions. I will first answer to the simpliest one:

Why do you think Afghan villagers want to accumulate savings?
Why do poor people need to accumulate savings?

The question seems a little out of the loop in first place. This basically comes from the circle of poverty theory.

Poor households do not generate enough incomes to cover all their expenses. So they have to make choices between members of the household to allocate their resources. Example: the household does not have enough money to buy clothes for all and send all to school. They will choose to buy closes for the oldest girl so she can get married and send one boy to school. All their choices are driven by a rational allocation of their incomes.

To be able to get out of this circle, households need to be able to generate more incomes to increase the range of choices. To increase their choices they need to be economically secure at household level. To reach this stage, vulnerable households need to accumulate goods or money so they will be able to diversify their production capacity. That diversification can be done through small business, acquisition of land, diversification of production, education… But all this need the household to generate savings they can use to purchase non basic/survival goods.

Also, accumulating symbolic richness as cattle or land or weapons is a way to show both your economical wealth and your social power. For young men especially, their capacity to show symbols as weapons, cattle, land is important as it prove to the communities that they are capable to have a family, to be respected as a man… So they will be socially accepted. You find this problematic in almost all post war context. I found it in places as different as Liberia or Somalia.
Finally, in Islam, being rich, accumulating symbols of richness, is being blessed in the eyes of Allah (Quite like in Calvinist approach of capitalism). So generating savings is something that most of the people will look at.
In traditional societies, the main point to understand is that group rationality lies at household level, not at group level. Vulnerable families will, as example, share with extremely vulnerable families but this is not a charity act. This is an expression of power and social domination.

About this, I would recommend to read Bourdieu : la distinction, critic social du jugement, 1979, edition de minuit. I know it has been traduced in English but do not have the reference. May be a little difficult to read and the link with Afghan society not clear at first look. But this helps to figure how the social habits are preserved and continue to drive individual relationships. What you have to keep in mind is that vulnerable households are self centered. Relations with others are symbolic power struggle. The group, let’s take the village level for the moment, will only prime on a very limited range of issues. And it will be driven by a limited number of influential families.