FWIW:
It doesn't matter how the information is gathered (POT vs opto-mechcanical vs optical vs Hall Effect vs ect), but how the device reports the info to the computer / PCB. "Absolute analog joystick" or "relative analog mouse" or "absolute analog lightgun". (Mame doesn't even care if it's an analog joystick or wheel.)
In directX PC's, what matters the most is the type the device and its driver say it is. For example, the driver says "I'm an wheel with a dozen buttons" and sends the computer that information in the standard way the windows expects said information to be sent. The device and its driver are responsible for translating any info into what the computer expects. It doesn't matter that the info is gathered with an opti-mechanical encoder wheel and two sensors (mouse like) or POT or Hall Effect, as long as the device & its driver translate it into whatever it told the computer to expect. There are other analog joysticks that use opto-mechanical or hall effect instead of POTs (nintendo 64 controller & dreamcast controller, respectively for example) and it doesn't mater, as long as you have the right driver and (if needed) adapter.
The opposite is true too. If the computer/PCB expects the info to be reported one way, but the device sends it in another, it won't work, even if the device collects the info the same way as a device that does work. The widest seen example is with spinners; most arcade PCBs (and optipac & optiwiz & mouse hacks) expect the info to be sent one way (quadrature signal on two wires), but some expect direction and speed on the same two wires and use spinners that send the info this way instead of the other. That's why some arcade spinners won't work on PCs or other PCBs (without hacking).
So, technically, mame see it as an absolute analog joystick, and treats it the same as, say, a PS dual analog gamepad. Not a wheel at all.
It's you that can tell the difference, and from what I hear, it does make a difference in favor of the logitech wheel being better than most other wheels, POT based or not.