What is the function of the tip end of the traditional bow?

As you can see from your picture, the bending function of this kind of bow is to increase the stroke of the bowstring, thus increasing the tension.

Recurve bow is a kind of bow that looks different from ordinary longbow from the side: one end of recurve bow's bow arm, instead of bowstring, bends outward. One of the special definitions points out that the difference between recurve bow and other bows is that recurve bow's bowstring, that is, the winding person, is in contact with its bow arm.

Compared with the straight-arm bow, recurve bow can store more energy, which makes the shot arrow have higher kinetic energy.