In the eyes of outsiders, Qiao Xuan was perceived as someone who only knew how to care for flowers and trees.
Moreover, she was already quite capable in the presence of the Emperor, and the Fourth Prince wouldn't gain much from her. Peony flowers didn't fall ill all the time, and Qiao Xuan's usefulness lay more in handling emergencies.
The Fourth Prince didn't need to go through so much trouble.
However, Shao Yunduan was different.
He had achieved the title of champion among numerous intermediate masters due to his genuine talent. He was an honest man with high moral values and fearlessness in the face of power. Most importantly, he enjoyed the Emperor's protection, which wasn't an easy feat.
Furthermore, anyone from the Qiao Family could easily discover the kind of family they were. It would become evident that Shao Yunduan must have employed some clever tactics to sever ties with the Qiao Family.