I don't what to say about this movie.
One thing is very certain. The Avant-Garde movement of the 1960s and 1970s is blatantly clear in the styling of this film. That alone makes this one work a significant, historical mile-post in cultural cinema.
Typically avant-garde, the film's sarcasm pointed at the bourgeois (capitalist) class is not only quite biting, but also quite humorous. It uses the juxtaposition of horrendously misfitting music as a means to an end. And it works beautifully.
Other than it's class struggle element, I'm not sure what else is relevant in the 21st century. But as historical cinema, it's clearly valuable.