M.B.
I believe that method is called "Touch Math", and is commonly used as a counting/adding technique, especially with students with math difficulties.....
I work with students with learning disabilities in middle school, and commonly see them using that technique.
I can see it as a learning tool, but I would be concerned that it discourages the students from memorizing the math facts, and relying on counting to add. We are frequently seeing students in middle school that don't have the basic math facts/skills as a "rote" skill, but are still relying on counting their fingers to add and subtract. (I saw this frequently in a 6th grade general education class..... at that point, they should know the addition and subtraction facts without having to count on their fingers.)