well, from reading the page and not being too familiar with python, it looks like some work to setup maybe upfront to someone wanting to use this, but doesn't know how to work with python.
In that case, the catch all cpanel would do the win for me.
Other then that ( and having used a catch all cpanel set up before ), I cant see any really huge glaring benefit to using a mailinator clone that couldn't be handled via catch all w. cpanel and maybe a bot/cron job.
I also know not everyone has cpanal available to them, so this script would be a win for situations like that where no license is available for those with no cpanel