Hallelujah I'm a Bum, like Rene Clair's A Nous la liberte or Le Million, is, from a film history perspective, interesting as an example of a movie that suggests alternatives to what was then becoming the conventional way of making sound pictures. That is: (1) Milestone's staging, which often made use of elaborately choreographed camera movements, and the strategic use of rapid-fire, rhythmic editing feel like techniques carried over from silent filmmaking; (2) the relationship between sound and image, though not as playful as that in Le Million or A nous la liberte, has more variety than that in conventional "talkies" (its most noticeable feature in this regard is the spoken-sung dialogue written by Lorenz Hart).
Its status as a kind of "transitional" film between the silents and the talkies comes through in the casting: Harry Langdon facing off against Al Jolson. Its take on socialism vs. capitalism also makes it interesting as a piece of history, but the movie has virtues that go beyond these curiosities. Namely: a fully-realized star performance from Al Jolson, a great supporting cast that includes vaudevillians Frank Morgan and Chester Conklin; some of Lewis Milestone's most inventive filmmaking. Milestone is operating here as what I tend to think of as a "full" filmmaker: that is, one who makes use of a wide variety or techniques and styles, rather than working with a more limited palette. ("Full" here isn't meant to imply that filmmakers who make use of fewer available options are somehow "lesser" filmmakers: both approaches are valid, but I do think they represent a difference in philosophy).
