I still am not sure how this would be different than using "events" from WT before they implemented the feature request to have all notifications be events.
Before WT made all notifications events here is what I ran into.
1) I set up WT so I get notifications every 30 minutes (time chosen by user)
2) I get notification that humidity is too low and since this is the first notification about humidity it becomes an event (all is good IFTTT now has trigger to turn on my sprinklers)
3) The sprinkler app (rainmachine) only allows you to turn on the sprinklers for a finite time then they turn off unless triggered again
4) After the sprinklers turn off, because of the time interval, I get another notification from WT that humidity is too low but since there really is no change in "state" from prior notification it does not become an event (new trigger)
I am not seeing how URL calling will work since I need to retrigger the applet but the "state" had not changed. I.E. after the sprinklers run for say 30 minutes and turn off if the humidity does not reach normal then I don't see how IFTTT gets a new trigger to turn the sprinklers back on since the "state" had not changed (it still just says humidity too dry but since it is the same "state" as before a new trigger is not created).