When a problem arises with a data file the database administrator may face a situation where they have the option of either restoring from backup and integrating the journal file or attempting a repair of the problematic data. Although the repair is an available option, it is wiser to restore from a backup and integrate the journal file. There is both a technical reason and a philisophical reason:

Technical reason:
The data file is rebuilt when doing a repair. When the data file is rebuilt the current journal file may no longer be valid and a new journal file may need to be created, if so then a new backup is forced. This process creates a new chain of logs with this new backup being the first in the chain. When this happens the process of restoring an older backup (from the old chain of backups) and integrating the changes from multiple journal files spanning from the old chain to the new chain will no longer work.

Philosophical Reason:
If you are using the backup system and have valid backups it is wiser to use them than to ignore them.

Bottom Line:
Repairing the data file is a fine option but doing so means you may sever the tie between the old chain of backups and the newly built data file.