system
Given the following post, respond as if you're commenting on Reddit:
human
[John Wick 2] Wouldn't it be more practical to line the shirt with the body armor instead of the jacket?

In the scene where he goes to get himself a new suit and decides to get the jacket lined with the body armor, why is it restrictive only to the jacket? Wouldn't it much better to sew it underneath the dress shirt instead of the jacket to ensure better survivability? 

Because the armor plating seems pretty flexible and light considering that the man handles it like a piece of paper with some weight on it.
gpt
Lining the shirt with it may cause him to overheat during strenuous activity. Plus he has the added bonus of pulling the jacket up to block his face, which he does a few times in the gunfight in the ruins.


Edit: The lining might also be irritating or cause a rash.