Is it really 'friendly'?
"The majority of material in a chip is support. We only use less than a couple of micrometers for everything else, ..."
Isn't that true for silicon base chips as well? Silicon is not poisonous.
If the cellulose base degrades, doesn't that release the gallium arsenide (etc) active components? If a silicon chip is disposed of, at least the metals and other compounds are safely and physically locked into it.
It may be that the driving force behind this development is the energy and other costs of manufacture, especially for short run batches of specialist devices.