I have 355 packages installed on my system.  If I want to reinstall all of
them, or install them all from
scratch on a new host, I cannot write the full list of fully qualified file
names on the rpm command
line, as this will break my shell command line length limit.

The pipeline

  cat package-file | xargs rpm -U

is not a solution, as it will do several, independent calls to rpm, some of
which mayh fail due to failing dependencies.

rpm ought to be able to read all package file names, and indeed also such
flags as --ignoredeps and
--oldpackage from an input file.

[I have asked for this since the days of rpm-2.x - so now it's in bugzilla
;-) ]