In the case of audio, would it be accurate to think of a potentiometer as a fader between two inputs?
A pot can be used as a fader between two inputs, but not at constant power, so it's probably not a particularly useful way to think of it.

Here's the problem: suppose you have a 10k pot with an input attached to each end and the output coming out the wiper. When the wiper is moved to either end of its range, you get full volume out of one channel and a severely attenuated contribution from the other. When the pot is set to the middle of the range, both inputs are attenuated equally, but they're not at half-volume-- they're much quieter.

In the case of audio, I think it would be better to think of a pot as a single-channel fader that has an extra lug on the end.

(I don't actually know whether in real audio equipment the extra lug has some use that I haven't thought of. Anyone know?)