What is the benefit of “tw monitor” over “tcpdump”?

The benefit of fw monitor over tcpdump is that with fw monitor, you can see the inspection points, which cannot be seen in tcpdump. Inspection points are the locations in the firewall kernel where packets are inspected by the security policy and other software blades. Fw monitor allows you to capture packets at different inspection points and see how they are processed by the firewall. Tcpdump, on the other hand, is a generic packet capture tool that only shows the packets as they enter or leave the network interface. References: Check Point Security Expert R81 Course, fw monitor, tcpdump