So the LLM makes up a reason for why it used an emoji

This reminds me of how split-brain patients would confabulate the reasons for the actions performed by the other brain:

A patient with split brain is shown a picture of a chicken foot and a snowy field in separate visual fields and asked to choose from a list of words the best association with the pictures. The patient would choose a chicken to associate with the chicken foot and a shovel to associate with the snow; however, when asked to reason why the patient chose the shovel, the response would relate to the chicken (e.g. "the shovel is for cleaning out the chicken coop").

https://en.wikipedia.org/wiki/Split-brain