When he says camera trickery he means that he doesn't edit anything. when I say camera trickery I mean that the camera must be at a certain angle for the trick to work. If he has a mirror for example and the camera moves a step to the right, the mirror is suddenly not aligned properly to my field of view and the illusion doesn't work.
The hobbits in Lord of the Rings is an excellent example. Nothing is edited in the shots but it relies on a very specific focal length in the camera and carefully planned forced perspective. It's impressive and a technical feat but it not "magic" like card tricks are magic.
It's a catchy name and it was among the first examples of the effect in the internet era that amplified the effect many fold. There is no reason for me to know about Streisand's house and there is no reason for me to know about this painting. I have only know about them because the internet exists.