To add to what xmprt and msephton have said, people have told me they use it for:
- Storing results for scientific research
- Local analysis of data exported from server-based databases
- Experimenting with database designs before exporting SQL to codebases
- Maintaining relational data where a website or app are not needed (eg. tutors keeping client records)
- Recovering data from databases used by other products (eg. phone backups, discontinued apps)
