It was written before Korngold's move to the US, so I doubt there is much related to musicals in it, although I'm not an expert. It reminding you of movie music could be because Korngold was one of the first Hollywood film composers, and essentially, a lot of the Hollywood sound in movies from the 40s and 50s was pioneered by Korngold and immitated by others. It is his own style, rather than being derivative of anything.
IMO his early operas fit well into the post-Wagner musical landscape of Europe, with composers such as Strauss and Zemlinsky, and Puccini was strongly influenced by Wagner as well. Operas from the early 20th century are interesting for how each composer deals with the Wagner question...