http://www.atomic4.com/faqres.htmMost definitely it's a heat sink. In order to read about how a resistor set in ceramic can function as a heat sink, I offer the link above to better inform you on what the resistor does in a primary ignition circuit. That is what the ceramic is all about and that is exactly what it's function is.
Your link does not even support your statements.
I don't know where you get this from, but I can state definitely, you are wrong.
Wire wound ceramic resistors are for high heat applications. They may or may not include a heat sink in the design, but the ballast resistor does not include one and the heat sink is not part of the resistance in applications that use one, which I will once again state does not include the ballast resistor.