If im holding a baby and he or she starts to whimper or cry I imitate the faces and sounds and they tend to stop crying. Did you ever try this? Why does it work?
its called the sunrise method its tried and true with special needs kids too. its when you enter into their own world and then they feel safe and on the same ground as you.
One of the innately pre-developed abilities of a newborn is emotion. When they cry, the cooing of their parent is a way of communicating empathy, and calms them.
Imitating a baby in their face may cause them to stop crying, but I would wonder if it is beneficial for their emotional development.
I think the sunrise method is more to sympathize than to immitate like the OP.