Explaining the Death Star plans isn't the point of the movie though. It's really a movie to say "okay, you've seen the Rebellion through the eyes of the heroes, and the Clone Wars from the point of view of Jedi. Now let's see how it looked like from the point of view of the random soldiers that were also there and aren't mentioned by name"
It's really a movie to show the other side of the revolt against the Empire. (And, even though it's not a movie, Andor continues this idea and is giving us a frankly impressive result)
And really I'd say that just the fact that Rogue One is really the first movie to give some room to normal, non Jedi people makes it so important.
Explaining the Death Star plans isn't the point of the movie though. It's really a movie to say "okay, you've seen the Rebellion through the eyes of the heroes, and the Clone Wars from the point of view of Jedi. Now let's see how it looked like from the point of view of the random soldiers that were also there and aren't mentioned by name"
It's really a movie to show the other side of the revolt against the Empire. (And, even though it's not a movie, Andor continues this idea and is giving us a frankly impressive result)
And really I'd say that just the fact that Rogue One is really the first movie to give some room to normal, non Jedi people makes it so important.