Pins 2 of both U1A and U2A are both so called 'virtual ground'. Due to the amplifier architecture, the opamp tries to keep the non-inverting input and the inverting input at the same potential: the voltage at the voltage divider R3/R4. C2 makes this potential coupled to ground for AC.
We are talking AC and pin 2 is 'virtual ground'. This means that the input impedance of the left stage is fully defined by R2 and the input impedance of the right stage is defined by R7.
Due to the high amplification of the right stage with the given ratio R10/R7 and the requirement for practical resistor values R7 will be relatively low. Thus the right stage has a relatively low input impedance equal to R7 (2k2).
The left stage however has a low amplification R5/R2 = 1 and again for practical resistor values are chosen. The advantage here however is that both resistors can be relatively high (100k).
So the role of the left amplifier stage is a high input impedance for the source voltage. The source voltage is probably a microphone, low voltage and only able to deliver very low current. Only with a high input impedance that source will deliver a signal with a low distortion.
The actual input impedance is R1//R2 = 50k.