This is my favorite white chalk pencil! The pencil makes a line that you can see and it brushes off well. It sharpens to a nice point but please note that you don't really need a sharp point on your chalk pencils.
The chalk line that you draw around your templates is part of the seam allowance. The line should turn under completely so that you don't see it.
FYI: If your pencil breaks every time you sharpen it, you probably need a new sharpener. I recommend the Palomino Blackwing Pencil Sharpener.