As part of my EDC I have a jacket appropriate for conditions. 
So do I, but getting caught away from my gear for some(unlikely) but possible reason is why I have a mini-kit.  If it is a hot day my jacket may find its way into my pack and if I become seperated from it I may really wish I had at least something to use if I cannot retrieve my gear befor the weather changes.
It happened to me once so It could happen again.