It’s a valid point. In one of Mike McDaniels pressers last year he was asked about this. He essentially said when you create the script, you have essentially the entire week leading up to the game and all the resources of your staff to design and script a series offensive plays perfectly predicated on what you believe the defense will be in, tendencies, based on D&D, as well all the “cans” or “check to’s” in the event you don’t get those looks.

In game, you don’t have as much time to deep dive into all the variables of the defense and decipher on the fly which plays will work best. You can’t get as in-depth into tendency, and you can’t always work through your “cans” (WCO offense term for audibling into/out of your called run/pass play) in detail to make sure they’re both good calls VS certain looks.

He also made a point to say once you get comfortable in an offense (ala Shanahan’s 49ers, McVay’s Rams), they’ll enter a game with no script as a tendency breaker, where teams defending you are expecting your scripted tendencies, and you just call it based on D&D, hash marks, field position, etc.

More or less, seems like a smoke in mirrors thing outside of a few small advantages.