Good one. I had never considered this.

Well, if you want to be serious, non lethals are always better to use because you can actually practice with your friends at trying to hit people with them in combat.

Also, can we talk about the fridge horror that Hermione may very well right about her priorities here. A witch gets killed and they just stick around as a ghost, whereas if a muggleborn gets expelled they get their wand snapped and all memories of magic/their magical friends erased, all the while any of their enemies with magic can trivially track them and their family down and attack them without them being able to defend themselves.

Even just the basic magical creatures and pests they’re learning about in Defense could likely pose a real danger to them, as I highly doubt you make eleven year olds take a mandatory self defense course otherwise.

At best, all the time and childhood memories of you and you’re family trying to piece together the mysterious occurrences around you, all of your magical relationships, even just the sense of comfort and community that came from you going from alone in the world to finding a social space made up of thousands of people just like you, all just completely wiped from existence.

Death by contrast just means being a ghost or passing on with the soul wizards have scientifically verified to exist or whatever, not necessarily as scary a thought to a twelve year old.

Or maybe he didn’t want to use one of the three unforgivable curses that would give a lifetime in Azkaban