If a smart gun worked 99.5% of the time, go try to market such a device to a law enforcement agency or even the military. Go on. I'll wait.
Now that you've become the laughing-stock of gun salespersons to those groups, what did you learn? You need to vastly boost the reliability of such devices before even
thinking of trying to sell them to serious buyers. Once the device failure rate improves by a few orders of magnitude, then try again. The
actual number the military is looking for is of far higher reliability than a 0.5% error rate.