Stats, Accountability, Progress Tracking, Automation.
We use our bug databases to track stats such as:
- Find rate (per tester) - how good are your testers x how buggy is your code)
- Fix rate (per dev) - how good are your devs x how nasty are your bugs
- Bucketing - which features are the buggiest / who's writing the most bugs?
- Estimation of when milestones will be hit based on bug slope
- Work Items & Suggestions - we put this stuff in our databases as well, not just bugs.
Other nice bits of data you can get out of your DB:
- What's being tested?
- List of fixed issues to perform regression testing against.
- Historical data! We track all of our projects, and compare their respective bug slopes.
- One source for all communication about bugs
Also, without a bug database, where do you store automated bug reports? Any project with some reach will generate thousands of user bug reports / automated crash reports. Automatically stuff this stuff into your database so you're not spending tons of time juggling emails.