The main utility that I see to this trick is, for example, if we make a component and we want to distribute it as shareware, this it will only work if the IDE of Delphi is being executed.
The main window of Delphi (class name) is TAppBuilder, this is also worth for C++ Builder that uses the same name for the definition, for we use it the function of the called API FindWindow, it would be this way the thing:
if FindWindow('TAppBuilder', Nil) <> 0 Then
ShowMessage('Delphi y/o C++ Builder se está ejecutando) else
ShowMessage('Delphi y/o C++ Builder no se está ejecutando);