I am not aware that any of the users on the forums I manage use this feature.
I use it but only rarely, usually when I need to sort out a profile issue with new users before I upgrade them to "Member" or another custom group.
Providing a user's email address continues to show on their Profile screen so that it can be copied that would be acceptable to me.
Given the trend to using more secure email protocols and the report here:
http://support.nabble.com/Bug-in-nabble-s-mail-forms-tp7608953.htmlI guess there is little option but to remove the feature.
Volunteer Helper - but recommending that users move off the platform!
Once the admin for GregHelp now deleted.