This dialog lets you have some additional control over the visibility of Revisions in the Revision list on a sheet (assuming your title block family uses a Revit revision list).
If you hide a revision cloud in a view using the right-click option "Hide in View > by Element" you'll find that the revision is also removed from the listed revision on the title block. You may not realize it until later if you are hiding them in the view and printing them out later (ouch).
If you do hide them this way then just remember the Revisions on Sheet dialog, you can turn them back on there!
