Goldfinger wouldn't be Goldfinger without "Goldfinger." What we mean by this confusing blend of italics and punctuation is that the movie wouldn't be the same without its iconic theme song, performed by Shirley Bassey. Composed by John Barry, along with the rest of the score, the "Goldfinger" theme is repeated throughout the film for two reasons: 1) To create mood. 2) To sell singles.
Yes, on a commercial level, the studio wants audiences leaving the theater humming "Goldfinger" incessantly, so they either have to fry their own brains with a laser or buy the soundtrack in order to extract the song from their heads.
But the repetition also creates a mood within the film. It reminds us of Goldfinger, even when he's not on screen. From off screen, he still influences the action. Also, Barry incorporated parts of the classic Bond theme into the "Goldfinger" song—seriously, go listen again. That technique increases the audience's ability to identify with the song, but it also reminds us that Bond and Goldfinger—the characters, not the tunes—have some similarities.
For example, take this lyric: "For a golden girl / Knows when he's kissed her / It's the kiss of death." Well, Bond Girls have a disturbing tendency to die shortly after getting busy with James Bond. In Goldfinger, a whole family line is wiped out after sisters Jill and Tilly Masterson both die after becoming entangled in Bond's web.
The song, of course, emphasizes that the kiss of death is "from Mr. Goldfinger," reminding us that for Goldfinger, the goal is death, like when he paints Jill gold. For Bond, death of the women isn't his goal, but it's still an unfortunate side effect.
Maybe in the end they got off easy, though: they're not the ones with the song stuck in their heads until the end of time.