As an electonics labs person I applaude all efforts to mske our practise more renewable. However this is a circuit that I would have wired without PCB at all, directly point to point, wire to pin.

Better than a greenwashed alternative is to avoid using msterial that is not necessary. Yet one also had to consider the whole lifetime of a product: ten throwaway circuits versus one very durable one etc.

They’re investigating “can circuits be produced from”, not asserting “this is a better medium for this exact circuit”. It is a tutorial on creating clay PCBs at all, a demo of the technique.