Thats right, they had idea but FaceID module is too much thick to be able to fit in lid of the laptop (MacBook). Not sure but it’s like 0,5cm of space, see comparison below.
Beyond mere engineering problems, there's the question if it's even a good idea. You can hold your phone at a slightly different angle when FaceID fails the first time around, but tilting your not even height-adjustable iMac or MacBook? And you have to double-press a special button to signal the system that you even want to be identified anyway. So why not just keep the TouchID button?
There is potential utility in features like Center Stage and Overhead Camera on the Mac. But for that you only need a wide-angle camera and face detection software, not necessary a LiDAR scanner and laser dot matrix emitter. Some of those more advanced sensors are only useful on a phone or a watch. MacBooks don't even have GPS. So why a distracting notch on a Mac, when you even hide it on a phone?
Despite its clumsiness Continuity Camera might be the best long-term solution for all your filming yourself tasks on a Mac. Just glue your phone on the back of your Mac, when you need it there. The notch is not even necessary and will eventually disappear, when a reasonably good iSight camera fits in the smaller bezels again. It's a failed experiment design dead end.
