It's because I leave the racquet sagging when I raise it initially, for me personally, it allows me to accelerate harder towards the point of contact after the trophy position to get the most out of my kick serve
I don't personally pay attention to the start motion, because I'm more focused on the end motion - the swing after the trophy position, as long as you can get into that position, I don't think it's important as much how you get there, because if you do end up there, you've got to be doing something that's more along the lines of something right than wrong
Case in point, I can also comfortably do pinpoint stance serves, and my swingpath and setup is different, but it still works for me, just because I'm more concerned on the final sequence of the swing
Things like that is where your own preference / form / timing kicks in, rather than the base fundamentals, anyone can setup the way they are comfortable with, as long as the base is still there