It's simple, really. Getting this off 4 times against good players isn't terribly likely, and it feels sort of character-victim dependent. But I do this, once or twice, quite a bit. It's not fantastic, but it's a generally good basic sort of thing to try. It does do good damage quickly, at least, and from there, you can switch to a more cautious game of going for kills in any number of ways.
-As for spiking at the end if your near an edge- yup. It can work. Good stuff- if you use phantasm, some characters like to get near the edge because the risk of flying off makes you hesitant to try it, even if you know the distance perfectly. Well, just don't try living a game off of this, it's just one sort of basic thing you can try to rack %.