Doing product research or any research for that matter, is about a convergence of data points. As such, here is the winner of the Cardsharp's POV on the little handy wallet knife:
I've used it a few times and have been more impressed than I thought I'd be. The knife is a unique solution and, as you stated in your review, with a form factor like this, there isn't any reason to not carry a knife. I haven't used it nearly long enough to tell, but I wonder if the flexed areas of the card will eventually fail due to folding stress/wear. If that ever happens, I will let you know. The solution is a bit gimmick-ey and the cardsharp's design would not suffice for a frequently-used EDC knife. However, for backup or occasional use, I think its fine.
Thanks, and thank you once more for the Cardsharp.