Sure, we can burn plastics. But that can be problematic, because they often contain metals (either as filler, or in multiple layers) and are typically contamina

Sure, we can burn plastics. But that can be problematic, because they often contain metals (either as filler, or in multiple layers) and are typically contaminated. In a closed system, where you're just cracking plastics, it's arguably easier to deal with contaminants. And I also suspect that you'd use less energy overall.