I can't imagine something more interesting than radiation levels. Video? Boring. Audio? Even more boring. Maybe WiFi or other radio signals? Still radiation is much more interesting then those mundane things.
I thought it was kind of dull/simplistic in the "geiger counter" sort of sense. But was imagining maybe weird radioactive isotopes or dangerous chemicals or precursor type of things. Wouldn't think RF-related things would need a spy walking around with an ipod. But who knows -- maybe something for air-gapping systems. Lord knows you and I will never know. ahahah