When Alex Honnold free-soloed El Capitan, the exact point was that he didn't have a rope. He had a desperate urge to challenge himself with bigger and more difficult tasks.
This is like asking why a parachuter would need to bother to pack their shoot correctly before going on a jump.
Or why a race car driver would bother to wear a seat belt.
'Having a map' might be the #1 thing he could do to ensure his survival, as he probably would have been able to walk out were he to have done this.
He apparently was not suicidal, and probably didn't intend on dying. His 'preparations' were not really 'preparations' so much as they were the actions of a stupid, glib or over-confident fool thinking that he was prepared.
He literally turned down the offer of 'reasonable gear' from someone thinking that he wanted to have a more 'natural experience'.
"Hey maybe you ought to wear a seatbelt of you're going to go for the land speed record"
"No thanks, I'm good, I want it to be more 'natural'"
This is the framing point of stupidity: mountain climbers, BASE jumpers, race car drivers take risks of course, but they're not stupid about it. The risks make sense in the context of what they are doing.
This is not the story of a man seeking enlightenment, it's about an otherwise entitled moron (not many kids have big college funds to 'give away') who stupidly and unnecessarily died.
"Let's give away money and go play on the highway" is what the book should have been called.
You said it wasn't a story worth telling. History says it was told by published article, book, and then a movie. And it's obviously of note enough that people from around the world make a pilgrimage there, that they've removed the bus, that the bus removal is international news and that people will still visit the site where the bus was!
It obviously resonates with some people and not with others. Some get it, they understand the motivation, it means something to them. It's OK to not be one of those people.
It 'proves' that an idiot, thinking he was taking 'basic precautions', but really was taking none at all, walked blindly to his own death, can be twisted by authors and narrative makes into some kind of 'insightful' story.
It 'proves' that populism is for fools who can't take the time to just see what is in front of them.
"A man decided to fly an airplane without any training or knowledge whatsoever and died on takeoff - here is the story of his enlightening journey"
Filmmakers dramatize and re-interpret events all the time.
There is no 'real-life story' other than a moron who went into the deep wilderness without even a map. And were he to have taken even basic precautions, would be alive and well.