If you tell me, "I was there", I imagine some time in the past, and I picture you 'there' at that time.
If you tell me, "I have been there", I imagine that if I looked through
your diary, I would see an entry that said you were 'there' one or more
times in the past.
The "story" is that
you were there.
"I was there" actually
tells the action of the story.
"I have been there" just says that the action of the story happened.
It says you have the experience of having been part of that story.
CJ