The Instax film is capable of much more than the $50 cameras that use it can produce. I bought my wife an Instax printer, and she shoots photos with her iPhone, then spits them out wirelessly to the film. Kind of a backwards work flow, but the quality of the shots is MUCH better.
What is happening with Instax is it's dying because of the cheap plastic cameras and meniscus lenses. Why Fuji won't just make a decent metal body with an X-mount lens for Instax I'll never know.