Why is Gold Diggers of 1933 considered a classic movie musical?

Gold Diggers of 1933 is considered a classic movie musical primarily due to the innovative and spectacular dance sequences staged by choreographer Busby Berkeley.12

The film is celebrated for several key reasons:

• Visual Innovation: Berkeley defied the stage-bound conventions of the era by using camera angles and movements impossible for a live theater audience to experience, such as his signature overhead shots that captured performers in precise, kaleidoscopic geometric formations.1
• Memorable Production Numbers: The film features iconic musical sequences, including "We’re in the Money," "Remember My Forgotten Man," and "Pettin’ in the Park," which showcased Berkeley’s ability to create a dazzling, opulent fantasy universe.12
• Backstage Narrative: As a quintessential "backstage" story, the film effectively integrated its musical numbers into the production of a Broadway show, a formula that defined the era's popular musicals.13
• Warner Brothers Style: The film balanced its extravagant musical numbers with the gritty, urban atmosphere for which Warner Brothers was renowned at the time.1