I've been thinking about natural burial for the last couple of years, and was very happy to hear a podcast about it.
I think there are two very tangible benefits to be derived from it.
First, for the family of the deceased, the increase in involvement
should help with the grieving process. As the family digs the hole by hand, builds a casket, etc. they will have time to process through the concept that their loved-one is gone. We see all too often these days people who are unable to let go. This is evidenced by the way we prepare the deceased for an open casket funeral - preserving and making them up so they look like they did when they were alive.
The second benefit is for society as a whole. I think it's a great thing for people to have a physical location that they know is the resting place of their loved one. However, how much land is filled up and untouchable with bodies of people that no one remembers anymore? I much prefer the idea that as soon as my descendents no longer care about where I am buried, there is no physical marker on that spot to indicate someone is buried there, no taboo from stepping on that place. I love the idea of having graveyards be native-plant forest reserves instead of manicured lawns where 90% of the property is tabood for foot traffic.