In the same vein as Little Caesar, Public Enemy launches a trend of escapist crime based films that cater to the Great Depression audience wanting to see people with money get gunned down and watch a little guy rise up to the top. This film moves again down the track of fantasy and providing escape along the tabloid lines to the now poor masses who just want to be mindlessly entertained by criminals fighting the system. (Interestingly there can be a parallel of this desire drawn to the late 2000’s/early 2010’s as our nation experienced a similar cultural paradigm shift from the Great Recession, people clamor to see fake versions of themselves taking down anyone as if they’re getting vengeance for their real world economic problems)
Jimmy Cagney is great, you’re seeing the idea of a "Celebrity" emerge from these films, mostly because of their voice and the ability of audiences to relate to them with not just viewing their actions but also hearing their unique sound, of which Jimmy Cagney's is unforgettable. His voice can be picked out of any crowd and that's what made him so compelling to watch perform. His machine gun rapid fire style of shooting out lines was his signature. And this rapid pace of talking became part of the movement of talking picture shows of the 1930’s and 1940’s. He speaks insanely fast, sometimes unintelligibly so. This pace of dialogue delivery is absolutely an American invention, with some British similarity, but most other talkies from foreign directors allowed their actors to be a bit slower or more realistic with their performance.
Again you're seeing a distinction between American cinema which thrives on spectacle, entertainment and stimulation, and foreign cinema which takes up the mantle of exploring the human condition and social issues and trying to portray reality onscreen.