[jggimi]

Per pf.conf(5):

:network    Translates to the network(s) attached to the
            interface.
.
.
.
Host name resolution and interface to address translation are
done at ruleset load-time....
.
.
.

...Surrounding the interface name (and optional modifiers) in
parentheses changes this behaviour.  When the interface name is
surrounded by parentheses, the rule is automatically updated
whenever the interface changes its address.  The ruleset does not
need to be reloaded....