ADXL355 Self Test

Hi

I have several questions about the self test feature of ADXL355 as follows. Could you please let me know ?

Q1. What is the purpose of the self test ?

Q2. Regarding datasheet, X-Axis is 0.3g, Y-Axis is also 0.3g and Z-Axis is 1.5g at Ta=25degC. When Ta will change higher or lower, will the output value also change ?

Q3. The customer tries to use the self test to adjust the output drift due to the temperature changing. Is it possible ? 

Regards,

Hiroyuki