That is a great kit, thanks for the post.
I have one pretty similar for camping. I figure the idea is to be able to stabilize a bad cut or other injury, for the time it would take to drive out to a location to get medical attention. The further away from medical assistance you roam, the more stuff you need.
I added a container of a prescription burn treatment called Silvadene. Worth its weight in gold if you have a burn of any significance.
Another thing I've thought about, but have not added, are some of the bleed-stopping first aid materials like HemCon strips or QuickClot. What is your opinion on that?