It's there for cutting. In contrast to the nakiri, which lacks a pointy bit for poking and cutting in narrow places, the santoku adds versatility with this little nubbin of sharp metal.

Once you start using Japanese knives, you will probably never go back to Western style knives. Understanding the reason for each type and the art of using them will open a whole new world of texture to the eyes and to the mouth when experiencing food. I would highly recommend a fairly new book given to me by a friend who knew my love for Japanese knives, called "Japanese Kitchen Knives". It will show all the proper techniques for the use and care of these most needed tools of the kitchen. Once you master their form and learn how to sharpen with a water stone, you will believe.

Sorry, I get very passionate about certain aspects of cooking. . . .knives are my most coveted tools in my kitchen.

I would venture to guess that when you chop you aren't resting the knife blade and pivoting it on the cutting surface but rather on the tip where it won't dull the blade and it pivots easier.