Chen Mou is trying really hard to ensure that Zhang Ren killing Pang Tong is definitely not a fumble by Pang Tong by showing that Zhang Ren is a skilled strategist, politician, powerful fighter, and a godly archer. Also I said this before, it's quite eerie how generals from Shu seemingly loyal and devoted to fighting against Liu Bei but those same generals are also going to be loyally serving him.