“‘OverSight’ takes a different approach. Instead of requiring you to cover your webcam, it’ll notify you anytime someone attempts to access it or your computer’s microphone.
It continually monitors your system looking for malware, such as OSX/Eleanor, OSX/Crisis, and OSX/Mokes, as well as others that attempt to spy on macOS users, according to the website. If it detects an intrusion, you’ll get a pop-up notification to alert you.” – The Next Web
It is all a matter of trust… Do you trust a freeware tool made by a former NSA guy? Or do you fear the NSA or even worse: cybercriminals smart enough to install something that controls your computer, including access to your cam?
I would suggest a layered approach here: anti-virus, anti-malware, firewall (like the annoyingly useful Little Snitch), password managers, DNS protection AND probably this tool.
Why? Because webcams are not too high in the hierarchy of hackable stuff in a computer. Once a professional hacker gets control of your device he will probably not stop at trying to use your webcam. So you would be better to protect your whole body rather than just being naked wearing only gloves before you go out to throw snowballs.
Though not necessarily the main targets of criminals, webcams still pose a nice threat. A study by Campatch a few years ago showed that half of the survey participants use their laptops in sensitive areas (44% in the bedroom, 8% in the bathroom). So if a cybercriminal, a terrorist, or the secret service of any country decides to turn some attention to your cam it will most likely end up being fruitful for them… and probably shameful for you.
So if you have already taken necessary precautions against malware, tape and firewall up for good!