Do I need to worry about packed primers at the GHC?

Question

GHC has an extra (inner) layer that simply wraps the primitive known in accordance with the requirements of Intabstraction.

data {-# CTYPE "HsInt" #-} Int = I# Int#

As a GHC user, have I ever expected to use it other than understanding that STG will generate type code -# 1#?

Are there any known cases where the GHC generates wrapper code? If so, why?