sunapple
macrumors 68040
1. The edge on the MacBook/iMac is too thin for the depth sensing camera
2. Completely unnecessary expense. How often do you have to log into your Mac compared to a phone? Most people just leave it open for the whole day and maybe only log in 3-5 times a day. I log into my phone closer to 100 times a day. Mac users would rather the cost is spent on more powerful components and decent cooling.
1. On a MacBook I could see the challenge, on an iMac though? Compared to the iPhone X?
2. By your logic TouchID would never have been added. It is however much more secure and faster than the passcode, so it does have a reason to exist. TouchID is being phased out. FaceID is the only solution out of the two that makes sense on an iMac. Cost will come down at some point.