Zip ties can help you out in various situations. Maybe something comes loose and you need to secure it or you need to do some trailside repairs are in order. I have had use for them on the road on rare occasion. For a dedicated hex wrench those can be handy when you need more leverage or have a specific thing that needs tightening that requires something longer. Some people also just like having their most used hex needs in an easier to use package. Everyone's kit is going to be specific to their wants and needs.

I certainly have odd wants and needs in one of my kits as most people don't need a T40IP but I want to be able to remove my Bosch motor bolts on one of my e-bikes in an emergency as maybe the shop I am near is not equipped with that bit or tool. Very few people would want or need that tool but it was something I wanted, that kit also doesn't have a 6mm hex because I didn't have anything on the bike that used it so it is a very odd set up.