PWM Mode on DRV8301

Hello ,
I 'm trying to understand odrive firmware and I get through DRV8301.
I want to know is there a difference between 6 PWM INPUTS MODE and 3 PWM INPUTS MODE.
and why did you choose n 6 PWM INPUTS MODE despite it’s easier to deliver the 3 PWM and let DRV8301 generate PWM signals for low side internally.
I am kind of confused . Thanks.