I'm almost done with a current playthrough and I am resisting choosing the "I promise I'll keep you safe" option because Astarion is not weak and this dialogue option implies he is. Not only that, but Astarion's reaction to it at first shows it's not an appealing concept to him either, that he needs a great protector. Astarion is as capable in combat as my character. Are there any consequences for never choosing that line for the rest of the game? I won't if there isn't.