Why is a potentiometer connected in a two-wire circuit?

Question

Electronics

Answer 1

You can connect the third output to the middle one - it will be even better, because with poor contact between the slider and the graphite track (with a half-dead variable resistor), the resistance will not go into megaohms due to a circuit break, but simply jump to the maximum on this resistor.

Answer 2

Why is a potentiometer connected in a two-wire circuit?

A variable resistor has been called a potentiometer due to the fact that on the middle pin it allows you to change the potential, that is, the voltage. But sometimes it is the resistance that needs to be changed, the third output is not needed for this, and then the same variable resistor is turned on only at two ends. I'm hinting that in your photos - not a potentiometer.
If you let in a bit of trolling, then you can add another reason - saving wires (two wires are cheaper than three).