Computer-generated imagery in movies is a common thing when it comes to blowing up stuff in space and showing giant robots fighting in downtown Los Angeles. But here are some examples where you may have never thought computer graphics were used.
Visual effects artists are getting better and better. Realistic compositing requires quite a number of skills that include not only abilities to work with video editing software and 3D, but also the ability to understanding light, motion, and physics. Although we, the viewers, tend to favor more scenes shot in-camera, there are times when pleasing us is more expensive than creating the effect in post. The VFX companies are aware that the audiences are more sophisticated today and expect realism, which means bad CGI is not at all acceptable.
In the examples shown in the video, we can see that sometimes the audience thinks a scene is computer generated just because it doesn't exist in the real world or it's expensive accomplish with practical effects while they won't think computer graphics were used in another because it looks like a common situation within a well-known environment. The latter case is where production companies decide to be bolder when deciding if CGI has to be used. While viewers expect a dinosaur or a 100-foot robot to be fake and try to find glitches in the compositing, they won't be that critical when a city skyline is added in post.