Field help (AOEEANWRK) 

If this box is not checked, the workflow events relating to the basic operations (creation, modification in object management mode) are not called any longer. In this way, if imports are started and generate mass updates, the release of a multitude of events of this type is avoided, which could impair the performances of the import and cause the mass sending of messages.

This does not means nevertheless that the workflow events relating to the release of the import are disabled.