These days, technology is advanced enough to allow secure video calls with 4K quality between any two people around the world. In those virtual conferences, they can discuss anything in total privacy, on secure channels, while seeing each other as if they're really there.
Yet, world leaders fly thousands of miles, and spend lots of money and efforts on actual face to face meetings with other leaders. (Recent two examples: Donald Trump and Kim Jong-un, Trump and Putin)
Why is that? What's the benefit of personal meeting face to face?