Paradoxical not to use as a CLI? I don't see how. Certainly that's not what Perl was developed to be. 3 out of 4 parents in your list aren't CLI's either.
I suppose the motivation is to put its features more at your fingertips, moreso than perl -e already does. I often use the debugger for that purpose. Do you have a simple example of something you'd like to be able to do that you can't at present?
But God demonstrates His own love toward us, in that while we were yet sinners, Christ died for us. Romans 5:8 (NASB)