So I sent this to a friend of mine who owns and operates a crematorium and a funeral business.
This is his reply:
"The practicalities are somewhat different though, as you can imagine. Cemeteries are not designed to permit the size of hole required. Lifting the deceased into the hole requires a crane! What about obese people? Leakage? and trying to fit someone with arthritis and brittle bones into the cocoon?
It looks nice on paper, - but is impractical.
Lovely for babies though
Interesting nevertheless.