One is that he worked as a middling chef for decades and only had his breakout success in his 40s. I think this made him much different than your generic essayist/journalist, and also let him speak to different kinds of people. He became a symbol that international travel, trying new things, and living life to its fullest doesn’t have to be an early 20s thing followed by decades of monotony.
He was also uniquely principled (he’d finance some episodes himself) and speak to people on all sides politically, without pandering to either.