I think you are assuming that the person on the downloading side is someone understands that Perl has command line options beyond "perl myscript", knows how to find and read perlrun, isn't scared to use options other than the script name or -mSome::Module, and knows how the command line options interacts with CPAN::Config, assuming they even know there is a CPAN::Config . That is likely true for a command-line comfortable developer who is selecting modules for a project, but not necessarily for someone just looking for a ready-made bit of functionality to use on their website.
Nor is it necessary true for an experienced developer who "grew up" using GUI development tools and only occassionally uses Perl. The mechanics of turning code into software is often a mystery to them, some sort of black magic that happens when they click the build button. Even the need for a "make" program is confusing because they have no real understanding of how the process happens without a GUI.
However, it comes down to philosophy - should our goal be to make a package that can be installed without a burp for someone who thinks everthing should be point and click (or command w/o options and enter) or should it be aimed only at people who are agile at the command line and comfortable looking up command line options?