A pointer is an absolute locator of a byte in the address space of a process, while an integer index implies a certain base (start of the module-private array)

A pointer is an absolute locator of a byte in the address space of a process, while an integer index implies a certain base (start of the module-private array) and a multiplier (object size). By using handles, "user code" is freed from having to know the base and the multiplier, which allows for a more compact locator that remains constant in case of base/multiplier changes.