Use case
Return the date of the last time that the status of the current issue was changed. If it was never changed, return the creation date.
Expression
Create and configure a Smart field using this expression in Jira Expression parsing mode:
issue.changelogs.filter(changelog => changelog.items.some(item => item.fieldId == 'status')).map(changelog => changelog.created).concat(issue.created)[0].toString()
