I disagree. This is something I make use of in Codify, where the plugin has the ability to export a code snippet to a temporary script, in order to prompt the user to save the file to their device (see # Script Injection). The reason for making the generated script unarchivable is so that the temporary script isn’t saved during autosave.
I do, however, agree with hiding the property if it’s still at its default value. This wouldn’t disrupt any part of my plugin’s functionality, and still ensures that temporary Instances aren’t saved during autosave or publish, in cases where setting something as unarchivable is relevant.