I don't know much about these things but other posts on Reddit about tiny cameras usually show they have wires.
I guess they're too small to include a battery, a bluetooth/wifi chip and antenna, and a smaller wireless technology might require more expensive receiving equipment? (I'm mostly guessing here.)
https://www.reddit.com/r/oddlyterrifying/comments/nskvry/camera_in_a_furniture_screw/
It's too bad file system code isn't easy to verify. It would be great if there was a file system that was formally verified (https://en.wikipedia.org/wiki/Formal_verification).