What is the contribution of HINSTANCE in Win32 Child Windows?

Question

I know that the parent window requires a HINSTANCE that is used by the processor to identify a specific process in Win32 API Windows.
But what if I don't provide HINSTANCE for the child windows like
Button
Static
Edit
Listbox
Listview
... Etc
Will that make a difference if I provide the HINSTANCE a NULL in those child widgets? Will the HINSTANCE of parent not be enough to identify it's children?