The only module I can find on my machine with a ::Simple counterpart is LWP, which has LWP::Simple.

Here is the explaination that the author of that module gives.

DESCRIPTION

This interface is intended for those who want a simplified view of the libwww-perl library. It should also be suitable for one-liners. If you need more control or access to the header fields in the requests sent and responses received you should use the full object oriented interface provided by the LWP::UserAgent module.

I guess what this means is that Module::Simple presents, what is in the opinion of the author, a simple interface to his/her module