Low Budget Visual Effects

A thing I learned from this article is that the COTOPOXI boat (That appears to be huge) in "Close Encounters of The Third Kind" was actually a 20-foot model and the actors were just placed a quarter mile away. Another Thing I learned is that the "Imperial Sand Dunes" from Star Wars Episode VI were actually just dunes in Southern California (Not Surprised). I also Learned that the author of the blog post used the same "Forced Perspective" technique in his own movie "The Grind" to put a humvee in the desert. A thing I liked about this article is that it gives you a useful way to make a low cost visual effect. I also liked that the author included videos of the effect in action. A question I have about this article is why does everyone do this effect in the dessert?