Agreed. And, I can't imagine a full-metal body cam's internal parts surviving a bang that would damage the guts of a plastic body, either.
But, on the other hand, I do understand the significance of having a dust and water-resistant camera when out in the field shooting in the Amazon jungle or Kalahari desert. If they wanted to, they could add those features to a full-plastic body.
Yes those features are more important to me than mag alloy. It's all marketing, you have to pay for mag alloy to get weather sealing. Plastic nowadays is a far cry from when plastic was labelled as a cheap substitute for metal. Plastic bodies now are rock solid.