What are the checkboxes in outline mode for?

This has got to be a simple question, but its answer has eluded me. I use the current version of DTP (1.3beta3) and have found it to be fantastic. I have just begun to use its outline capabilities and noticed the boxes that can be checked or unchecked. So far, though, I can’t discern any difference in behavior between a checked and unchecked box. What does checking a box actually do?

The manual only says this:

By making groups and documents checkable, DEVONthink Pro can also
be used as a very simple outliner. Unlike other outliners, DEVONthink
Pro uses documents as items and groups for items that have sub-items. technologies


I don’t think it has any functional effect, other than to signify that this part of the outline is Done or Pending, In Progress, Up for Grabs, Undecided, and so on. In other words, the human operator assigns a value to the check mark. Sneaky, eh?

Thanks so much for your response… that thought had occurred to me briefly, but I figured, no, certainly there’s some feature I’m missing here!