system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does diplomatic immunity exist? What's the benefit?
gpt
It exists because every country wants their own diplomats to feel safe when working in other countries with very different laws, and the only way to guarantee that is to give the same courtesy to others.

Imagine a world without such immunity.   Canada appoints a woman as deputy ambassador to Saudi Arabia.  She gets arrested and sentenced to jail time for driving a car.  Massive international incident ensues.  This can all be avoided with immunity.

Incidentally, it's not total immunity.  A country can choose to waive it for a serious offence, or can bring their diplomat home for trial under their own laws.  This happened some years ago here in Canada when a Russian official killed someone while driving drunk.  Canada could not prosecute.  We asked Russia for permission to do so, they said no, and then recalled him and jailed him in Russia.