Because I like having options, and I don’t like missing out on plot or dialogue if I don’t have to. She’s an interesting character that I think would have good interactions with the rest of the party.
Because I was playing a good character, which meant that if I wanted the tieflings to live then Minthara had to die. With the update, there is a canonical path for both the tieflings and Minthara to live.
There is that, but I feel the changes with Minthara count; I’d have liked to have had her as a companion, but I’d already killed her and was multiple hours into act 2 before the patch allowing her to be saved and recruited into any party was released.