Apple has responded to the tempest in a teapot that resulted when the TrueDepth camera was covered in a review, and Animoji still worked, by saying that, yeah, it would somehow work, but the experience won’t be the full quality its developers strive for.
The iPhone 8 and 8 Plus, it turns out, which also have the A11 Bionic processor and ARKit support, could have in theory been enabled for Animoji, but the resulting facial expression tracking would be nowhere near the level achieved with the depth mapping available on the iPhone X. That is why Apple isn’t … – Source