I mean, of course they're going to spin it so that it sounds like they chose Touch ID over Face ID because it was more practical to the user but the real reason is that they can't build all the Face ID tech in a small enough package to fit in the MacBook Pro's notch. That's the main reason. If they'd put Face ID on the iMac, it would have looked odd not having it on the later released MacBook Pro. Once they can produce a wide angle Face ID setup on their laptops then they'll probably go with that. Or they might just offer both.
Of course, the reality is that Touch ID might actually be just as practical as a Face ID implementation now because they use a physical button that you have to press. Without that button, you'd have to mouse over something and double click or press enter in the right box to get it to activate FaceID just like you have to double tab the button on iPhones and iPads.
In terms of the touch screen, honestly, having a touch screen on a desktop OS has such minor uses that it really doesn't seem worth it and I say that with an office full of Surface Books. It's really only practical to use for scrolling the occasional document and the mouse wheel is just as good at that really.