Are practical effects really better than CGI, or is the claim itself a trick?

Each side has its case, and the claim itself needs a careful reading, because the best-known practical films also use computers. A practical effect is produced physically, without computer-generated imagery or other post-production techniques. Their case is the one made for animatronics: a physical presence moving in front of the camera in real time. The case made for CGI is control: it lets filmmakers do many effects more safely and convincingly and, as technology improves, at lower cost. Practical effects need heavy planning, and a mistake can be expensive or impossible to repeat if the effect destroys something.

Now look at the films that advertise their practical side. According to director George Miller, 90 percent of the effects in Mad Max: Fury Road were achieved practically, and none of the Doof Warrior's scenes used CGI, even when his guitar shoots fire. Yet the film also contains 2,000 visual effects shots, from altered lighting and time of day to weather and terrain replacement.

Christopher Nolan's Oppenheimer used real explosives for the Trinity test and forwent computer graphics for it. Many fans thought he had set off a real atomic bomb, and he called that flattering and scary. Nolan claimed the film contained no computer-generated effects. But the final film had several hundred VFX shots made by a mostly uncredited crew of around 160, and the studio DNEG made more than 100 of them from more than 400 practically shot elements.

So the honest summary is a blend. Practical describes what was built and filmed in front of the camera, and computers help join, clean and extend it.