That socket looks stout, and the lack of a hinge should keep it sturdy, but I suspect the more compact folding shovel and a dedicated hatchet or bushcraft knife might serve me better under most circumstances. On the other hand, being able to swap to a longer handle and use it as a polearm might have a practical advantage, even just for digging.
I'd just choose a metal cap or small spike, but probably not as much a spear tip as just a counterweight.
!PIZZA