Then I don't understand your argument. If you're just saying what could go wrong with heap corruption, then your vtable complaint also applies to storing function pointers in arena allocators in Zig? Zig doesn't have anything special here?

I asked you what's wrong with pool destructor function pointers. You gave a reason what's wrong and I refuted it. So no, I'm not saying that storing a function pointer is special, just that nothing's wrong with it. (And implying that since there's nothing wrong and it's probably the most straightforward thing to do, it's also probably the right thing).