The Power Of Practical Effects
There are two main kinds of special effects in movies.
First, there's CGI, or Computer Generated Imagery. CGI is the kind of special effects that we are accustomed to in most modern movies. Beginning somewhere in the mid-2000s, CGI became much cheaper and therefore ubiquitous. CGI began to be seen everywhere. For a very good illustration of this, try watching some 90s TV with special effects sometime, such as the X-Files. The X-Files has 90s effects before CGI became widespread, and it's striking how primitive they look. Many of the special effects used in older television shows are less about convincing you it's real than they are about "evoking" the effect or suggesting it. For example, in the X-Files episode where time stands still temporarily, the screen just changes colors and brightens, and this is meant to vaguely suggest that something supernatural or alien is happening. Since the mid 2000s, this all changed, because technology was advanced enough that everybody and their brother could do CGI. Thus, CGI became ubiquitous.
Second, there's practical effects. Practical effects are effects that are really present. For example, in the original Star Wars movies, Chewbacca's arms are actual props that had to be built. In the Neverending Story, Falkor is really a giant puppet. In Jurassic Park, which did use some CGI, an enormous T-Rex head was built to look more convincing close up. Camera tricks, such as filming someone from below to make them look taller, are also a kind of practical effects. This also includes stop-motion effects, such as the ones used in Clash of the Titans.
The power of practical effects is not just that they're realistic. And, indeed, many of the practical effects in the original Star Wars look more real than the CGI exactly because they're practical. But on top of that, practical effects are also good for bolstering CGI. The CGI in Jurassic Park looks so good, in part, because it's backed up by practical effects. The tyrannosaurus head looks like it's really there because, in many scenes, it is really there. Mixing practical effects and CGI is a very potent tactic because it causes CGI to age well. Another good example of this is in Lord of the Rings. The CGI in Lord of the Rings looks somewhat dated, but it's still relatively convincing. And this, in turn, is because there's a lot of practical effects mixed in to make everything look more real.
There is a reason why many Star Wars fans make a point of looking for older editions of the films. That guy you see at the comic book store in a Star Wars t shirt might just own a much older edition of the films, just for the sake of seeing the practical effects.