Why (TRASH CINEMA) Matters by Justin Oberholtzer, the Cinemasochist
Take for instance the creativity at hand in a trash film. Usually, these films will exist in their own universe, not adhering to standard practices. This adds a layer of inventiveness that can make one's imagination run wild. This could be good enough, but even some grindhouse flicks have a clever, underlying message (the anti-drug message in "Coffy" springs to mind). Not that it's necessary. Bringing joy to an audience is just as important, if not more so, than having a profound message.
Even the truly awful films matter!
They can serve as study pieces to analyze what went wrong in a production. They're also good for showing that, despite a film's low quality, it could still have passion behind it. Ed Wood is regarded as one of the worst filmmakers of all time, but he clearly loved making movies and thought he was doing good. He wasn't making bad movies on purpose. He put his heart into his projects, only for them to fall flat. This gives his films a weird charm.
To bring it back to the joy argument, terrible movies can do this as well. As the Cinemasochist, I'd argue the best (worst?) ones bring more joy than some of the more challenging, technically rewarding films. The "so bad it's good" category, or fun failures as I refer to them as, can be both an entertaining experience, as well as a learning tool. You get to unintentionally laugh at the train wreck, while also analyzing what went wrong. This brings both joy and education, a rare feat.
So, the next time you shove that trash film down into the depths of the bargain bin, do remember that heart was put into it. That it may seem like a cheap cash-in (and chances are it is), but there's time and effort put into it. That, even if it fails miserably, you can still learn from it's mistakes. More than you could possibly learn from a great film. After all, you have to sit through the worst films to truly appreciate the best ones.