This is a small thing. But, like the Elmsley Count issue in this post, it bothers me when I see it and I think it's an easy fix.
I find a lot of people perform David Williamson's Striking Vanish so it looks like this.
Tap once. Tap twice. And it vanishes on the third.
That's fine and all, but I think it's a mistake to do the two little practice taps before the actual vanish. I'm guessing the reason people do it is because it helps them get in the rhythm they feel they need for a kinetic vanish such as this. But the problem with it is, no matter how skilled you are, you have to do something different on the third tap or the coin would remain where it is, as it did in the first two. And the fact you have to move your hands differently than you did in the preceding taps draws attention to the fact that you're breaking the pattern you've established (the pattern you've unnecessarily established).
I almost can't even intentionally do it as bad as many people do. Watch this dude try and do it. And he thinks he's good enough to teach it.
One tap. Two taps. FISHYMOVE! vanish.
To me it looks more like what you're actually doing than what you're pretending to be doing (which is almost never a good thing in magic).
I do think it's a good idea to establish the idea that the coin is going to vanish when you tap it, but instead of doing two practice taps on the coin and then a different looking tap to vanish it, I tap somewhere else. "The coin will vanish when I tap it," I might say, tapping the air in front of me. Then I do the striking vanish. Because I haven't established a pattern/rhythm of tapping the coin, there's no pattern or rhythm to be broken.
If the GIFs aren't clear, here's the raw video with one version following the other.