in natural setting i agree.
but people do act. dating / courtship. getting photos taken. some better actors than others but most adults follow social scripts and facial expressions go along with much of that.
i understand the problem you have with the imposed artificially mapping faces onto models that have a different body – like face transplants.
its uncanny valley. almost unholy territory.
and yet: the person is long dead. its amazing to have a photo. we have that technology.
its amazing we have even MORE technology today, to animate 160 year old technology.
a photo does not reflect a person as it is.