I clearly don't understand the audience that video is supposed to be for.
If it was scare the western world, it's only going to give the leaders better arguments for making a moral case against these barbaric sociopaths.
If it was scare the muslim world... From what I've seen on reliable news sources, those countries that were on the fence or were somewhat ambivalent about ISIS are now in the "Let's obliterate those crazies before they attack us and/or we get lumped in with them!" camp
If this was to somehow garner credit in the jihadist world and show that they're the most jihadist of the jihadists, I don't think that worked for them either. You have to admit, that even when Al Qaeda is calling you crazy, that says something. I'm sure they'll pull over the fringe players who don't think Al Qaeda is violent enough, but not enough to offset the massive casualties they're taking at the hands of US air power.
The only thing that I could see this as a ploy towards is to try to drive a wedge in and alienate moderate muslims from the western world. Something along the lines of "See the crazy thing we're doing, we'll we're muslim, and since you're neighbor is muslim you should think of them as being as crazy as we are!!!"
My only problem with that is that these people just don't seem that well planned. It seems like they're making it up as they go along and not doing a particularly good job of it. Killing the pilot, let alone in as grizzly manner as they did, got them nothing and only hurt them unilaterally. Holding on to him and trading him for prisoners would have demonstrated that they were people that could at least been negotiated with. Strategically this was a dumb move.