What do Egyptians think of natural burial?

In Egypt, Muslims bury their dead in a fairly similar way (they cover the body in a certain way and just bury it into the ground directly) . Christians have cemeteries (each family buys a building and puts the caskets in there). I think each has an advantage and a disadvantage. Of course natural burial is cheaper, you get to save a lot of natural materials (wood, metal etc.) but the problem is.. i heard that back in the years, it once rained heavily in Egypt (extremely heavy rain) and the bodies came out and floated on top of the rain water (muddy water) .. so idk