ADS1115: why need a OPA333 in the Figre9-6 of datasheet

Part Number: ADS1115

Tool/software:

in my desigh, need to monitor the current shunt.

in order to reduce the circuit, i directly connected the Rshunt to the ADS1115's INX.

is ok ?

becasue the ADS1115's FSR(±0.256V) and LSB(7.8uV) is enough.

and the FSR is form -0.256v to +0.256v, so i no need use the OPA to do level dhift.