This JQL function is used for searching for users by checking against user properties that contain date or date-time values.
usersWithDateTimeProperty(propertyName, operator, value) #Output: User list
If you want to search for issues where a user as a specific text or numeric property value, have a look the the usersWithTextProperty or usersWithNumericProperty() function.
If you want to search for issues, checking only if a property is being set ignoring it's value, have a look the the usersWithProperty() function.