(Original Idea text has been edited)
I commonly receive locations in DMS format on paper forms, and I need them to be in DD format. In ArcMap, I simply open the Go To XY tool, enter the DMS coordinates, and it returns them in DD format on the fly. No need to run geoprocessing conversion tools, install Add-Ins, pick input/output coordinates, etc. The Locate Tool only captures a small part of the Go To XY functionality.
The Coordinate Conversion Add-In (Coordinate Conversion | ArcGIS for Defense) helps convert on-the-fly but coordinates need to be setup instead of just automatically configured as they were with Go To XY. Also it has more limited functionality than Go To XY. At a minimum, this should not be an Add-In, but just included as a basic navigation tool in the Pro installation.
There are several other features that Go To XY provided:
--Pan to location
--Add graphics at location (e.g. a point and/or a text box)