WordPerfect Office Ideas Portal
Because one forgets to save the document periodically and end up losing your work. Power goes off unexpectedly, one is distracted and some countries have load shedding i.e. the power can and does go off unexpectedly.
The current (2021) manual states:
To set timed document backups
1 Click Tools -> Settings.
2 Click Files.
3 On the Document page, enable the Timed document backup every check box.
4 Type a value in the minutes box.