There's hundreds of those kinds of books. And yes they are interesting to read and they kindle the imagination. But they are all 'hogwash' and they only misinform you. Better read fantasy or SF literature which is known and honest fiction.
But their writers surely make a good living writing those books. So one wonders if they actually believe what they write, which I would not be very suprised about, or if they are consciously tricking people by writing down crazy theories people would like to see as being true.
And, if you get very one-sided information you can make everything seem probable. You can provide evidence for everything. But you need to look at the whole picture.
The way Eric von Daniken presents things seems very convincing. But if you take a step back and look at things out of the context he provided then you will interpret it way differently.
Micheal Shermer, a well-educated person and a leading skeptic, wrote a book called "Why People Believe Weird Things: Pseudoscience, Superstition, and Other Confusions of Our Time."
It has a chapter called "Why intelligent people believe weird things." It turns out that intelligent people are much much better at this than the less intelligent or more average people.
Real life examples are chess super-greats like Fischer and Kasparov. Both believe in totally absurd things. While Fischer is clearly nuts all over the place, Kasparov seems like a very reasonable person in many other things. His analysis of the politics in Russia seems dead on and he points out that his objective and reasonable analysis, which he learned in chess, is very important for this.
But then he does believe in 'New Chronology' as proposed by his friend Anatoly Timofeevich Fomenko.
This hypothesis proposes that all historical events we know actually happened after 1000 CE.
The reason Kasparov supports this because he cannot imagine human civilization going through the Dark Ages.
Intelligent people are better at coming up with totally far fetched or just crazy hypotheses. Furthermore, intelligent people are much better at rationalizing their stupid ideas.