The martial arts passed down in a lineage can be obtained by one's own cultivation without the need for exchange. Su Xin had known this for a long time.
At the time of exchanging the Blood River Divine Sword, the System had said that once the cultivation of the Blood River Divine Sword was perfected, the Blood River Divine Finger could be self-realized.
Now, Su Xin's use of the Three Finger Flicking the Sky, which led to a significant increase in the proficiency of the Twenty-Four Solar Terms Shocking Finger, actually shares the same principle with the Blood River Divine Sword.
The Three Finger Flicking the Sky was inherently the ultimate secret learned from the perfect practice of the Twenty-Four Solar Terms Shocking Finger. Although Su Xin was only using a consumable item at the moment, he already had a substantial amount of insight due to the foundation laid by the Twenty-Four Solar Terms Shocking Finger.