@tulfan great idea but I get very dubious too when I see paper based replacements for plastics.
As you highlighted some don't mention, is the energy used by sourcing, transporting and manufacturing compared to the plastic variant. Usually the latter is actually better for the environment for single use and on top of that especially where recycled or buried to capture the fossiled carbon.
Article doesn't mention if the cardboard is combined with a plastic fixer used to extend their durability especially in wet environments. Which makes recycling and composting it impossible.
Best alternatives are plastics made from plant oils and recaptured before their release into the environment.
Though saying this the idea is impressive and workable. Please don't show me the DE variant otherwise I'll lose it. Cardboard guards against the skin would be like nails on a blackboard to me 🙂