That's great, thanks for the reply and the links!

Now, it's not possible to use any of the current core modules to either edit or display these properties, aside from the Users page in the Admin menu itself, correct?  Are there plans for such functionality?

AFAIK none of the core modules utilise them at present. We'll shortly be adding a few nodes to the dnn file schema so that a module can indicate it's minimum dnn version - this will then allow us more freedom to use recent features without risking breaking i.e. at the minute if we used the the controls outside the core framework in other core modules, it would restrict modules to a particular dnn version and anyone who tried to use them for a version prior to that would break their install.

Please note this is an evolving item, the 3.3.5/4.3.5 release already has a number of items checked in in this area

DNN-3834/3835/3839 - Added ability to manage the profile visibility (enable/disbale and default) and to enable/disable the Services.
http://support.dotnetnuke.com/issue/ViewIssue.aspx?id=3834
http://support.dotnetnuke.com/issue/ViewIssue.aspx?id=3835
http://support.dotnetnuke.com/issue/ViewIssue.aspx?id=3839

Cathal