Having to do things for-real also kept things grounded. Modern action movies are often cartoon-like with supposedly human characters stringing together super-human moves that’d leave a real person with dislocated shoulders, broken bones, and brain damage, because they’re actually just CG, no human involved.
[EDIT] OMG, or take Bullitt (1968) versus, say, the later Fast and the Furious sequels (everything past Tokyo Drift). The latter are basically Pixar's Cars with more-realistic textures. They're cartoons with live-action talking segments. Very little actual driving is depicted. Bullitt may have used the movie-magic of editing, but someone did have to actually drive a car, for every shot of a car driving. Or at least they had to set up a car with a dummy to convincingly crash. What you're seeing is heightened, but basically within the realm of reality.
Or take A Bridge Too Far. It's a bit of a mess! Make it CG and it'd be outright bad. But ho-lee-shit do they blow up a lot of stuff, like, you cannot even believe how much. And look at all those tanks and armored vehicles they got! And planes! And extras! Those are all 100% real! AND ALL THE KABOOMS! And it all looks better than CG, to boot. The spectacle of it (plus some solid performances) saves the movie. Make all the FX CG and it'd be crap.
Imagine a Jackie Chan movie with CG stunts. What is even the point. It'd be trash.