Do Xbox One controllers have analog face buttons?
According to Wikipedia, the Xbox One only has digital face buttons:
11× Digital buttons
(Y, B, A, X, LB, RB, left stick click, right stick click, Menu, View, Xbox)
The same applies to the Xbox 360 controller:
The right face of the controller features four digital action buttons: a green A button, red B button, blue X button, and yellow Y button.
Interestingly, the original Xbox controller does have analog buttons, however:
6× Pressure-sensitive buttons
(A, B, X, Y, Black, White)
As for why Microsoft removed pressure-sensitive face buttons from its controllers, it's probably for the same reason why Sony removed them from the PS4 controller: hardly any game ever made use of the pressure-sensitivity, and hardly anyone even knew they existed.