I think people misinterpret FaceID. The idea isn't to spend time analyzing how it works or whether it's slower than TouchID or not. The idea is that it blurs the perception of needing authentication at all to unlock your phone.
I think what Apple was going for was using FaceID to take care of all the security stuff behind the scenes so you don't have too. It removes having to think about authenticating to access something because faceID has already detected that it is you.
I can also cite a few scenarios where Face ID is more convenient than Touch ID. For example, I can autofill passwords in the browser or unlock apps protected with Face ID without needing to raise a finger to authenticate, since Face ID does this automatically in the background for me. If I take a photo using the camera app from the lock screen and then want to share it with a friend, I still need to unlock with Touch ID, but with Face ID, my phone is already unlocked by the time I get round to this. And there's also the side benefit of my notifications being hidden from view when someone else wants to peek at my phone, yet they appear when I glance at it.
What you're left with is a phone that is as easy to access as one without a passcode. No longer do you have to go through security checks because it is all done automatically. It's all pretty seamless when it works.
It's in line with Apple's overarching goal of making technology more personal for the end user. That pretty much sums up their modus operandi right there - not necessarily to have their products have the most features, but to remove barriers that stand between technology and the end user.
