Different between traffic rules and port forwards

Hello, Currently I feel a little comfused about the traffic rules. I know the port forwards and it works well, just forward one port from WAN to LAN. But can I do it with the traffic rules? And what is the user scenario for the traffic rules.

As an example to traffic rules ........
You want to block traffic for specific device..

Simply speaking, port forwards are for rewriting traffic (altering source or destination ports and addresses) while traffic rules are for applying various policies on traffic (accepting, dropping, ...).

Traffic rules are commonly used in non-NAT environments or in conjunction with IPv6.