Hi,
The short answer is, "Yes"
A potentiometer is used when the user may have to adjust some parameter in the circuit. There are many different things.that may be made adjustable by the designer.
As Matt pointed out, one use is to adjust the gain of the op amp stage. Another use is for adjusting the output offset voltage, commonly called a "null" adjustment. This was more common years ago. There are numerous other possibilities here though just as there are uses for regular resistors. It all depends on what the designer of the circuit wanted to allow the end user to adjust. Another simple example is an adjustment for the output of a voltage regulator circuit where the potentiometer adjusts the reference voltage for the error amplifier.
For a better idea, take a look at some circuit with op amps and potentiometers and see what you think.