In the existing lore you can free the soul, use it for healing, ask it questions, trade it or ask it questions. In the structure of Descent into Avernus freeing the soul is the good decision but it's nearly impossible to be consistently good in that module because you will need to drive an infernal machine somewhere.
I would like the option to free it be added to the game. For me it's strange that the happy go lucky companion has such a chilling opinion about soul destruction.
I suppose to just take it as somewhat ignorance on her part and died in the wool of just having a use for em sort of thing.
