The scale piece that Jiu Nian kindly sent couldn't be destroyed directly either. Trapped here, Yang probably needs to study it, which will also take time.
The result of Jiu Nian's gamble was that Yang got his hands on research material. As long as there is enough time, it's almost like giving Yang leverage.
Yang already had shattered scales with dissipating Divine Skills as material. By researching that as the foundation, there is probably a real possibility of discovering something on that intact scale.
But none of this has much to do with Yu Ziqing, who had no intention of getting involved.
He now had a clear understanding of his own position; asking him to bury himself in following Yang for research was unrealistic due to the vast difference in foundational knowledge.
Whatever he wanted to research could only be limited to things he understood thoroughly, related to himself.
