Shared Parameter "Add to all .." Rational explanation?

[D_Driver]

I am looking for either Rational Explanation (semi rational explanations accepted) or a practical use for...the following little check box...

Setup:
Blank project from default template, create new shared param file that has 2 shared parameters 'X' and 'Y' as text parameters
add some walls, create a few rooms, create a room schedule:

Understandable but unfortunate wording:
view properties, Fields, Add parameter
Shared Parameter, select
pick X from the shared parameter list and ok back 1 dialog box to the parameter properties dbox
Check the box that says Add to all elements in category
ok, ok ok ok back until you finally land back in your schedule.
look at your project parameters, X is now a project parameter.
Don't you wish it just would have told you it was doing this? Not necessarily yet another dialog box, but rewording of the check box?

Questionable behavior (or where my real question lies)
same schedule add a field, shared param, Y
but this time Uncheck the box that says Add to all elements in category

Column shows up but is not available for editing
Property does not show up on the objects (not really surprising because I just told it not to) and is not added to project parameters

Creating a tag out of this shared parameter also will just show a ? and be un-editable

While I understand yes the schedule is reporting the parameter, and yes now the parameter is defined in the project, what use is this feature?


Rational explanation? or useful real life examples?

[Steve_Stafford]

Are you asking why it is an option at all since it is necessary to check it in order for them to work?

[D_Driver]

Are you asking why it is an option at all since it is necessary to check it in order for them to work?

Sure, or more along the lines of can you think of any useful reason to keep it unchecked? ie there are so many features of Revit that I look at and say "huh, that is odd" and then read in this newsgroup 10 different ways people are using that particular oddity in some really twisted and useful ways. Just wondering if anyone out here has done anything other than verify it is checked when they do this.