RogueLeader,
The motivation of this sequence is like Machete, to have IV be the first up in the order (which I think is essential), but also account for the recent standalone films and Lucas prequel(s) to have the entire Star Wars franchise into some kind of narrative cohesion.
I think while this type of bouncing back and forth may in the past have been dizzying, I think today’s audience is used to this kind of storytelling because of how much of modern television is told. Think of “Lost”, “Westworld”, “The Walking Dead”, “The Affair”, “This Is Us”, etc.
I think this kind of flashback storytelling can sometimes enhance the character and overall narrative, and shouldn’t be confusing when it’s just one film at a time.