Everything I need for comfort and safety is already in my pack; I have no need for a "survival kit." IMHO, the ones promoting those are trying to make money off inexperienced folks who don't know better.

If your pack contains the "Ten" Essentials, and you don't wander off and leave the pack behind, there's no reason to take anything else. I treat my pack as though it were my purse (it does contain ID, a credit card and a small amount of cash), and always keep it close at hand. If I dayhike during a backpack, the Essentials go with me.