Butch Cassidy and The Sundance Kid (1969)

Revealing mistake: In the opening sequence when Sundance shoots the gun belt off the card player, the film was cut to make the quick draw appear faster. You can see Butch's image jump across the screen in the background.

[After blowing up an entire train car while only intending to blow open the door.]
Sundance: Think you used enough dynamite there, Butch?

Trivia: The turn-of-the-century-style film (which plays alongside the opening credits) was originally intended to appear in the bulk of the story. On Butch, Sundance and Etta's trip through New York, they view this film, which depicts Butch and Sundance's deaths. It upsets Etta so much, it contributes to her later decision to return home by herself. The segment had an annoyed Butch and Sundance watching the film from the back of the theater, whispering comments like, "We never did that". The change was made when it was decided to make the trip through New York into a musical interlude over still-photos. The main reason for the change: the studio had just finished work on a "period" set of a New York street (ca.1900) for the film Hello Dolly and did not want this expensive set appearing in a different film first.

Question: What was the point of the dialogue between Butch and Etta when she wonders if they might have been a couple? There are no other moments in the film where she seems to want Butch more than Sundance so why bring it up for no reason at all?