1) Somtimes choosing different dialog options has no effect.
Of course. BUT they allow you to better roll play your character. If I am playing an a-hole and have 4 dialog choices that all have the same result, that's fine because I get to RP/choose the A-hole option.
2) You think you are given a false choice. "Give me the antidote!" Well in that set of dialogs you are able to use multiple skills depending on what your character is better in (Persuasion, intimidation, deception) and there is a path that leasd to her giving you the cure without having to kill her. So it's not a false choice.
