I'm slapping my head and thinking "this is such a great idea, why didn't I think of that?". I'm sure lots of other people are doing the same, and it's a sign of a truly great idea. Congrats on launching!
In my case, I actually did think of this idea! Just never had the hardware knowledge to even know where to get started (and I was worried about the trouble it'd cause as card skimmers used it to easily clone cards - hopefully we'll learn more about how coin solves that problem). I'm mostly glad they're trying to make this a reality, because I'd really like to get rid of all these membership/point cards that stuff up my wallet.
Yes. This happens all the time to me. I'll sit and burn out my brain trying to think of problems to solve... and I can never think of any then I see this and I want to just bang my head on the keyboard because it's just.. so.. simple.