Though, I generally like the idea of circuit traces embedded directly in mechanical design of a product, I suppose this would make devices completely and utterly non-repairable. Not that there's something new in this, but imagine, debugging a 3d volumetric circuit, where chips and discrete components baked solid into medium? And I also wonder, where such super high level of integration would be necessary, other than medical/wearable/implantable devices...
Design the "board" as a central component w/ one or more snap-on ocovers?
The smaller you can make things or more integral the more interesting you can do things - vape carts are a good example where it might actually reduce the total ewaste if the chip and the body were integral (though clearly would still create it)