Of all places to 'spy' on folks, on a cramped airplane seems like the worst. Most people will be 1) asleep, 2) pissed off, 3) eating shitty food, 4) watching bad movies. It's likely that they decided to shove in some cheap android tablets that someone else sold them. It's unlikely that they are actively watching everyone, though the possibility of them switching on the camera to watch/record you shifting in your seat to get away from your neighbor trying to use your shoulder as a pillow is always there.
For security a lot of (most?) new aircraft have Cabin Video Monitoring Systems (CVMS). Depending on where you are seated they may be able to see everything you do or just your head. An aircraft shouldn't be considered a private place, as you are probably already being watched.
In 2008 a study was carried out that attempted to use facial recognition to identify passengers for signs of terrorist activity [0], so maybe they are used for that.
On the other hand, as you say it was probably just cheaper to use an off the shell Android tablet that has a built in camera...
I used to go to a gym where the exercise machines all had Windows tablets built in. They all had a camera and Skype installed. I'm still curious who ever wants to Skype all sweaty during an exercise, but probably the same person who wants to Skype on an airplane.
I'm still curious who ever wants to Skype all sweaty during an exercise
Maybe a variation of this old meme might help explain: "The great thing about going to the gym isn't exercising, it's showing everyone online that you did."
At some point someone at SIA would have thought about covering up the cameras (surely?), I imagine it would have been:
1. Accept the OEM design (cameras uncovered) but possibly have to deal with people not liking a camera shoved in their face (camera active or inactive)
2. Modify the OEM design (cover the camera, costing money) and nobody even knows that there was a camera there in the first place
So I'm curious as to why they chose #1. A pure cost-saving exercise? Reserving use of the cameras at a later time? Didn't have the option of modifying the design? Didn't think people would mind the thought of being filmed?
https://twitter.com/vkamluk/status/1097008518685573120