I assume you mean is Joomlapack compatible with Joomdle and not Joomla as Joomlapack is written as a native Joomla extension.
With this assumption the answer is clearly yes as Joomlapacks job is to backup any Joomla related files and databases. We use Joomlapack here at Joomdle.com and all my other websites too.
As for using Joomlapack to backup Moodle files and data, this should be possible although I have never done it yet. In Joomlapack you have the option to include "Off-site directories" and "Multiple Database Definitions". I believe you will need the core plus version of Joomlapack though.
Today, I back up Moodle separately as it has its own set of backup and restore tools. Would like to try backing up your test Moodle environment and telling us how you go. Perhaps based on your feedback, I may switch to using Joomlapack for Moodel too. It would be simpler.
