A game where there are no consequences to your choices might as well not have choices in my opinion.
 

It's interesting to hear other's perspectives. With or without consequences I always follow my own morale code in game during the first play through. Then I'll typically go back and make different decisions to see how they play out. Whether it's an actual gameplay change or just a narrative change doesn't really matter to me. However, in HL I could tell that if I didn't answer certain ways then I wouldn't learn the dark arts spells and that I feel is an actual gameplay change as we would have less tools at our disposal and combat does change quite a bit if you have avada kedavra and certain talents. So I felt like I "had" to make those dark arts choices against my own morale choice or I'd miss out on a part of the game that I wanted to experience.

I too didn't understand why it was okay to kill with a left click, but not use a single spell to do so. The aversion to the dark arts the characters had would have been better in my opinion if our other spells either knocked the NPCs unconscious or some other non-lethal result. However, like you I thought if I'm killing them anyway why should the spell matter.

Unlike Bigeye, I appreciate the choices with or without consequences because I may or may not want to be a jerk to some characters, even if that's just a dialog choice - it lets me decide the tone of my characters reactions. I feel like I'm given the opportunity to be true to myself if nothing else.
 

Even in games like DDO where dialogue choices have zero consequences save for slightly changing the dialogue path that leads to quest bestowal I still ponder my choices and try to get some sense of the personality of the character I am playing.

I haven't played HGL, but I have to agree that the choice of whether to murder someone with "morally acceptable magic" or "dark magic" seems pretty odd and artificial.