I'm interested in either human composting for end of life, but it tends to cost significantly more than cremation, but not as much as burial. For a cost effective alternative I've researched "water cremation", which instead of burning the body and releasing it into the air dissolves it in an alkaline solution and sends it to the sewage treatment process. Costs tend to be similar to cremation.
Ultimately phosphorus may be the mineral resource that dictates the minimum level of mining needed by society, so let's recycle that. Cremation should be a good way to get the usable phosphate out of human bones.