Because he might fry his system if it is for the Amiga = A1000 due to the different pinout.
It's a reasonable question to ask as I am under the impression that at the time of the A1k the system was just referred to as "Amiga", later it was more common to actively differentiate between A500 and A2000.
The BBOAH or amiga.resource.cx might help.
Cheers,
McT