Zhang Zian's honesty allowed Zhuang Xiaodie to find the answers to some questions that she hadn't figured out before. It provided her with such a sense of realization that she wanted to hit herself on the forehead for it, angrily asking herself why she didn't realize it sooner.
The elves' presence reminded him that it was a dream, so he started acting. He could have performed better and spent more time with his parents in this dream. He could've said "goodbye" on the last day of the Golden Week, or come up with other reasons to postpone it indefinitely; she had given him wealth, freedom, and reasons to do so.
However, when he found that the elves' powers were greatly weakened and he might've not been able to protect them in this dream world, he decided to stop the dream as soon as possible.
It was likely a painful decision to make. For the entire third day of the Golden Week, he found himself in a dilemma. However, this itself revealed nothing.
