In 2001, image sensors and the electronics to drive them were far larger then they are today, an endoscope-style fibre optic isn't necessarily ridiculous if you only had a tiny hole to sneak through a thick obstruction.
Even today, a non-CIA-grade camera head is probably 2-3mm across and the optics on a fibre optic can be far narrower.
You can only have a pinhole spy cam if you have a void directly behind the pinhole.
Well, I assume they can do better than a £10 USB endoscope from AliExpress!
But even if you have some ultratiny thing hot out of a classified lab, fibre optics also keep the active electronics further away and harder to detect.
They probably don’t even have to bother, just hack the targets phone, tv, iPad, laptop to get every bit of content they consume and conversation they have.
