Have you ever pulled your phone out of your pocket or purse with the intent of using that little camera icon on the lockscreen to go straight to the Camera app?
And have you been thwarted by Touch ID responding so quickly that you had to launch the app the slow way by navigating to the home screen and tapping the Camera icon? I sure have, and I’ll bet you have, too. It doesn’t really take much longer to launch the app that way, but it feels much longer because you know there’s a shorter way, and you’ve been prevented from using it.
Drang’s commenting on a piece by Craig Mod that (among other things) criticizes Touch ID for being too good, in the sense that it prevents you from interacting with the iPhone’s lock screen.
This isn’t always a problem, but I do find it annoying sometimes, and Drang notes it as well.