This read-create AceObjectType field specifies the type of object, for example IP-based or MAC-based matching, this ACE uses to classify traffic. It matters because it determines which set of tuple fields, IP addresses, MAC addresses, ports, and so on, are relevant for this particular ACE's matching logic. For example, setting the ACE type to an IP-based type would mean its associated tuple pointers reference IP address and port criteria rather than MAC fields.