That's definitely a useful privacy feature - however, unrelated to the concerns from the article. It doesn't listen in to you or anything - just the type of API that's exposed can be use as some bits for fingerprinting.
Thank you, good point. My mind sort of raced ahead of the article ;)
Laptop manufacturers are starting to build in camera kill switches, see HP Spectre x360. Not sure how necessary it really is given you could just put a simple slide cover [1] on.