As the power rating of the MOSFET is increasing in the case of continuous current and the Max voltage rating, i see people drive the gate of MOSFET with a transistor. Could you explain the reason for. 

1)Is it because as the current drawn increases the gate to source voltage increases so a 3.3v logic cannot handle. 
2) If so why there is no second transistor at STEVER\_A- input.

VCC is LIPO voltage around 10-15Volts\*\*

[![enter image description here](https://i.stack.imgur.com/UbjiM.png)](https://i.stack.imgur.com/UbjiM.png)