pkg_check_modules in FindPkgConfig creates interface library

When called with the IMPORTED_TARGET argument, the command pkg_check_modules in the module FindPkgConfig creates an interface library. From the code of FindPkgConfig.cmake:

add_library(PkgConfig::${_prefix} INTERFACE IMPORTED ${_global_opt})

What is the point of making this an interface library? Why not just create an imported library? Making an interface library is inconvenient because we cannot link it to another target with the PRIVATE keyword.

Huh? Linking to INTERFACE libraries as PRIVATE works just fine. Do you have an actual reproducer case available?