Crash go the Chariots! Van Daniken at a certain point in his book wrote “I seem to remember the Bible saying....” regarding gold foil on the Ark of the Covenent.
Von D. could not even be bothered to open a book that is universally available book to verify and footnote a remembered statement in support of the central thesis of his book. Why would anybody need to ever take him seriously again?
I'm not sure anyone ever took him seriously. On the other hand, this came out in the 60-70s and there was a lot of flaky, drug addled ideas at the time.
I read it when I was 11 or 12 and thought it was OK for science fiction.