3-D notes are embedded in the model and can be used by anyone downstream. It could be a thread callout, a suggestion for set-up for the NC programmer/ machinist, etc.

Someday we will all work to ASME Y14.41 and there will be no paper drawings and not even any 'drawing' files. ALL INFORMATION will reside within either the part or assembly models.

As to your question about making notes parametric, I do not have any personal experience doing this, but the methodology is usually to give the driving dimension a name that makes sense. Then the dimension will be referenced by adding an ampersand (&) to the dimension name. So, if the angle is what you wanted to change by selecting a note it might look something like this: "&ang_dim" Don't know why one would create extra work like this. By picking the feature and right-clicking the mouse you can pick 'EDIT' and the driving dims will display. Just pick the value and edit it.