The firewall rules are not required in H_C, because the advanced user can block sponsors via SRP, which is much more comprehensive protection for the home users. Also, in the recommended H_C settings, both blocked sponsors and firewall rules are a kind of overkill, except some special cases.
Yet, firewall rules can be useful for not advanced users in default allow setup (SysHardener, CUP).
It is worth mentioning that firewall rules cannot fully stop PowerShell from downloading the payload (only some methods can be blocked). Also, the firewall 'Block' rule for the application, does not block its child processes. So for example, if the user applies the firewall 'Block' rule for cmd.exe, then the 'ping' command from the CMD Console (or command line) still can connect to the Internet.