This is a rather basic dramatic plot element: a trivial misunderstanding between lovers reveals their pride or strength of character and risks shattering their happiness. You will find it frequently, from kids' films like Shreck to romcoms to serious dramas. In Star Wars the misunderstanding is thankfully not milked for all it's worth. It's a Space Opera after all, not a contender for best drama.

It provides a way to build up tension between the two lovers and thereby creates suspense. It also creates a bond with the viewers since they are entrusted with privileged information. Viewers also witness a test of character and a bond deeper than mere sexual attraction: Han demonstrates that he is not a mere petty adventurer, that he has the confidence and required emotional sophistication to provide support and friendship when needed. It increases the viewers' affection for Han and respect for Leia's strength of character.

Any actual relevance to the logical development of the storyline is probably secondary. After all, if the Empire is nearing absolute control of the Universe, is this silly misunderstanding important?

This is a rather basic dramatic plot element: a trivial misunderstanding between lovers reveals their pride or strength of character and risks shattering their happiness. You will find it frequently, from kids' films like Shrek to romcoms to serious dramas. In Star Wars the misunderstanding is thankfully not milked for all it's worth. It's a Space Opera after all, not a contender for best drama.

It provides a way to build up tension between the two lovers and thereby creates suspense. It also creates a bond with the viewers since they are entrusted with privileged information. Viewers also witness a test of character and a bond deeper than mere sexual attraction: Han demonstrates that he is not a mere petty adventurer, that he has the confidence and required emotional sophistication to provide support and friendship when needed. It increases the viewers' affection for Han and respect for Leia's strength of character.

Any actual relevance to the logical development of the storyline is probably secondary. After all, if the Empire is nearing absolute control of the Universe, is this silly misunderstanding important?