The tracked time in projects represents very valuable information for the management. Dependent on the applied methodologies in planing and controlling there are many ways to use these data.
Instead of providing some predetermined report formats (see T3985) it would cover much more scenarios when these information could be exported in a generic format (XML, CSV etc.) so the user can decide how to use or process them further.
Included with extended possibilities to select a specific subset before the export (see T5150), Phabricator would just provide a nice way to collect data where they arise and offer an open access through common formats for further processing.