How many other 96 year olds have interacted weekly with all those prime ministers? And also met all the other significant figures in that time?

Churchill faced down (figuratively) Hitler and Mussolini, which makes him a heroic and legendary figure. (He was also a racist monster). Until yesterday, she was a living person who had actually talked to him at length, regularly when he was alive. That's amazing to think about.

Well yes, but that's not what your parent comment said. Normal people watch the news and see all the prime ministers.

Seeing people and events on the news is nowhere near the same thing as being a witness to those people or events. You have to be on the scene of, or at least nearby, the events or speak first hand to the people who are involved. News reporters are witnesses to historical events as well. Their viewers are not. (This is putting aside what the legal profession might consider a "witness").

I said she was a witness to many important things, which is absolutely correct.