Fan Speed Control

a heating element is a resistor, thats why it works. The FF uses these "things" to waste electricity.

A heating element is designed to produce a certain amount of heat at a certain voltage. They are generally made of materials that can glow red hot without failing. It does have a defined amount of resistance to work properly but generally they are not used in a circuit to serve as a resistor. Think of the heating element in your electric water heater. It has about 10 ohms of resistance but why would you use that as a 10 ohm, 1000 watt resistor? Plus, it would have to be submerged in water or it will cook itself and fail in seconds.

The air core wire wrap resistors on your fan were designed to be used as low resistance, high wattage resistors. You could probably use them as a heating element if you stay within there design parameters. Their datasheet would define their thermal characteristics and other parameters you would have to adhere to. There are other resistors they could have used that look more like resistors. They probably made the ones they used in-house for cost savings.

Short story: I was designing a 3-phase brushless motor controller years ago that required exactly 40A peak current. I needed a precise milli-ohm level current sensing resistor capable of passing 40A +margin in a small footprint. Tolerance stack-up of other components required this resistor to be tuned. I used large gauge enamel coated wire wrapped similar to your resistors. It may have looked like a heater element but its purpose was to create a precise amount of resistance.

I hope this helps