"When Marieke Havermans’ mother-in-law died, the family was given a catalog to browse through by the funeral home from which to choose the casket they wanted. 'Each and every one of them was basically dark, ugly and too expensive. For the most part, they were made of particleboard that was lined with leak-proof paper—which was not what we were looking for,' she said. 'Particleboard is a cheap construction material that emits formaldehyde. There’s no dignity in particleboard.'So she got together some polylactic acid (PLA) and some reinforcing fibers and voila! created a biodegradable plastic casket.
Havermans was convinced that there had to be a better way. Her idea was simple: 'Why not design a sustainable casket made of a natural bioplastic that would, in time, simply biodegrade? A casket that would not only impact less on the environment, but that would also be an attractive and affordable option for everyone,” she explained.'
I'm not sure that I see any "dignity" in PLA, but maybe others do. Further, PLA is only considered biodegradable in an industrial compost site, which is not the same thing as a cemetery.
Another sticking point is that here in the US, the use of concrete burial vaults is very common. The bottom of the vault is placed in the ground first, the casket is placed inside the vault and then the concrete lid is placed on top. The reasons for use of burial vaults aren't exactly clear. Possible reasons are to prevent the ground from sinking over time as the casket degrades. Or because it slows the degradation of the body in case it needs to be exhumed for a criminal investigation. Or (cynically), because someone wanted to make more money than just selling caskets and burial lots.
Regardless of the reason, the near ubiquitous use of vaults will probably prevent these caskets selling well here in the US. But there is one other reason that I don't see them selling well (and why I have to laugh at the idea of this casket): it's because biodegradable burial caskets have already been in use for hundreds/thousands of years. They are called "pine boxes":