It's also a matter of narative storytelling. The helmet cams are an important aspect of the plot. They need to be familiar so modern audience's connect with them visually and also be large enough to be treated like usuable objects later in the story.
Tiny imbedded nano cameras would make more sense logically but just wouldn't work for the story that needs to be told.
Tiny imbedded nano cameras would make more sense logically but just wouldn't work for the story that needs to be told.