I dunno... all those keys next to each other. And you know what? After 40 years of playing, I still occasionally hit the wrong one!!

Of course, when I make a slip up (they happen!), nothing breaks. You make ONE slip up with either of these tools with a 2B in your hands, you'll be lucky if it doesn't break.

It's kind of like saying that, as long as you are a professional race car driver, you ought to never have an accident. But of course, 99.9999% of all the cars being driven are not in the hands of race car drivers...