I was JUST checking this out like a day ago!
I will never buy ANY coin gaff\gimmick\etc. but this looks really good.
Though I think I figured it out, do you have to wear a certain shirt to use this coin?
The old wise saying: Never say never. I think Blackout is very good and I personally would highly recommend it. My magic might not be as evolved as your own, but I suspect that even this idea is good for any magician experienced or inexperienced and can be incorporated in many coin effects. You don't have to give up your sleight of hand either and you can show non-gimmicked coins which can be examined before and after the effect, though, the idea can be used in the process of performing the effect.