Right now I could download an app, take a video, and put multiple explosions in it with the click of my finger. It's that easy with computer. Back in the 70s it wasn't so easy. If you wanted an explosion, you had to explode things. That's just how it went. There was no safety behind computer code. These were real camera men pointing expensive cameras at real explosions. Star Wars is a movie with a lot of explosions, so it could not have been easy or safe to shoot.
I worked on a movie that used explosives to explode some toilets and it took about six hours to get the shot. It took so long because there were so many precautions that had to be taken. I can tell you one thing, they didn't let the camera anywhere near as close as Star Wars did.