delphi - Why not raise EInvalidPointer?

The Delphi documentation states :

Never raise an EInvalidPointer exception directly. EInvalidPointer is raised internally by the memory manager.

I'm writing a custom base class as an alternative to TInterfacedObject, following the RTL implementation as closely as possible, and see, by example, that TInterfacedObject in the RTL implements BeforeDestruction as:

procedure TInterfacedObject.BeforeDestruction;
begin
  if RefCount <> 0 then
    Error(reInvalidPtr);  
end;

Where Error(reInvalidPtr) raises EInvalidPointer through a variety of unit-scoped methods local to the RTL.

If I'm writing my own class, how should I implement BeforeDestruction? Why not do this? :

procedure TMyInterfacedObject.BeforeDestruction;
begin
  if RefCount <> 0 then
    raise EInvalidPointer.CreateRes(@SInvalidPointer) at ReturnAddress;
end;

Is there something special with the global InvalidPointer exception object declared in SysUtils? If this is a bad idea, would it be sensible to simply raise a custom exception here?