Friends thought I was joking when I said I wanted to see this film. I am not a Directioner. I’m a middle-aged man. For all practical purposes, those are opposites. I wanted to see it, though, for the same reason I want to see any documentary: to learn something.

Nobody expressed concern for my mental health when I saw No End in Sight (2007), Charles Ferguson’s account of Bush’s bungling of the Iraq war; or The Cove, Louie Psihoyos’ 2009 exposé about animal abuse in Japan.

I’m particularly fond of documentaries about creative or artistic types. If curiosity led me to movies such as Sydney Pollack’s Sketches of Frank Gehry (2006), or the granddaddy of the rock doc, D.A. Pennebaker’s Dylan chronicle Don’t Look Back (1967), would it be less likely to lead me to One Direction: This Is Us?

Hell, yeah. For the obvious reason that 1D aren’t artists or creative types. Of the band’s members (Harry Styles, Liam Payne, Zayn Malik, Louis Tomlinson and Niall Horan), only Horan can even play an instrument. They claim no genius for studio experimentation and admit they can’t dance to save their lives. None has ever written a song, though Styles dated Taylor Swift, and we know what that means: Yup, she wrote one about him (“I Knew You Were Trouble”).

What makes One Direction’s story significant is the mind-boggling fact that, despite minimal musical gifts and the brief period they’ve been in the funky hunk business (their first album was released in 2011), they’re on track to be worth a billion dollars by the end of the year. What I learned watching this film is that what it means to be the biggest band in the world has changed completely in my lifetime.

First, it was all a fluke. As we see in the movie’s opening, the guys each entered and were eliminated individually from the British version of “The X Factor.” That’s when pop puppetmaster Simon Cowell got the idea of combining the cute cast-offs into a group whose sole purpose was to rock the world of social-media-savvy girls. The boys’ fans literally tweeted them to the top. One day they were singing for music halls of swooning tweens. The next, they were singing in stadiums. Around the world.

Morgan Spurlock (Super Size Me) might seem like an odd match for a project as unabashedly promotional as This Is Us. He’s been mostly about promoting himself. As the movie alternates between concert sequences and backstage scenes in which the lads cavort, however, one realizes what attracted him. “It’s the closest to Beatlemania I’ve seen in my lifetime,” Spurlock has said. “If this can be a documentary Hard Day’s Night, we’ll accomplish something pretty great. And I think we did...”

So the boys are the Beatles, and Spurlock’s the new Richard Lester. Somebody’s ego has been super sized.

Don’t get me wrong. The Prefab Five seem like charming, sincerely grateful guys. They get that good looks and passable voices have taken them absurdly far. For his part, Spurlock makes inventive use of 3-D technology. The picture is trippy in places, making it more pleasant to sit through the forgettable songs than it otherwise would be. But Beatles comparisons? Please. One Direction is less a band than a business plan.

Albeit an incredibly successful one. How incredible? Guinness lists Paul McCartney as the most successful musician in history. He’s been at it for half a century, and Forbes estimates his worth at $650 million. Two years, one billion. Granted, these guys work their butts off, but I think we can agree this is one tour that’s a pretty magical mystery.