[Question] Why is uuid being used as a link?

[fixwhat]

I am working into expanding this plugin but have some questions:

• Why the uuid is being used as a connector in the parental relationship between tasks and projects? ID looks easier to handle. What I am missing?
• It seems that Gantt is officially a plugin but unofficially part of the core, since it does not have a separate database table for its needs but there are fields on core tables that refere to Gantt-plugin.

So I need to implement a 'sortorder' field so that tasks could be moved around the project. Do you have some guidelines that I can follow about this issue? Because creating a table 'glpi_plugins_gantt' seems the obvious choice but since there are fields on core that reference Gantt I am lost of how to proceed.