I think Cider9986's comment [1] on the OP covers it pretty well.

[1]: https://news.ycombinator.com/item?id=48700061

I don't understand why a photosensing pixel is meaningfully worse for privacy than the devices we already have. I mean, sure, you might not as easily be able to cover up your camera with tape, but even then a better solution which should be implemented anyway is a physical decoupling.

And as I stated above, I doubt this is meaningful for spying capabilities. Micro cameras are likely more suitable, for better or worse.