Merits/Drawbacks of adding object to root group?

Take the following code:

SimGroup *rootGroup = Sim::getRootGroup();
rootGroup->addObject(clipboard);

What are the merits of adding clipboard (SimSet object) to the root group other than organization?
Are there any drawbacks?

I am trying to create objects that I can keep persistent between missions. I am assuming the root group is a place I can put those objects. Is this correct?

Thanks,
Frank