I've read Jin Yong's other works such as The Return of the Condor Heroes.
Yes, I think it is a good material to study Mandarin. For example, at the beginning of the video, Xiaozhao said:
我叫小昭。
wǒ jiào xiǎo zhāo"
I am called Xiaozhao
我听小姐叫你'无忌哥哥',
wǒ tīng xiǎo jiě jiào nǐ ' wú jì gē ge ',
I heard that Miss called you "Elder brother Wuji"
你大名是无忌吗?
nǐ dà míng shì wú jì ma ?
Is you formal personal name Wuji?