If you have an end user who has turned on the option in the Workspace to receive emails, then the downside is that they will automatically receive an email for the work item instances that reach their Oracle BPM WorkSpace inbox.  This is not a good option for someone who receives many instances every day.

If you want to customize the standard email Oracle BPM automatically sends end users if they have turned on this option, look at the activityNotification.mail file located inside your <OracleBPMEnterpriseInstallationDirectory>\conf directory.