Transplantation of the Apple Pencil innards possible?

I read the Pencil teardown and understand that the outer plastic and inner metal shell needs to be destroyed. Are the electronic components still working after this procedure? Is the metal shell essential or is it a safety measure in case the battery decides to expand/explode?

Just food for thought: I have a 3d printer and wonder when the battery dies by age and usage if it is possible to either print or misuse a real ergonomic pen casing to transplant the electronic innards and additionally exchange the battery circuit to a swappable 3,7v ±5% AAAA sized battery and maybe add a on-off switch. Not sure if the lightning/bt pairing will be lost once you unpower the logic board, as apple designed the pencil to be permanently on/hibernation.

I know it may not be worth the hassle and newer and better revisions of the pencil will surely appear by the time the internal battery dies, but I am a bored engineer.