Who are you and what have you done with the real jackknife? Posting pictures and now using the term fixed blade, it's like you're an entirely different person.
I can definitely see the advantages of a small fixed blade. They're lightweight, convenient, and stronger than a folding knife. For some of us though they're not practical for everyday use. Fixed blades look out of place when wearing slacks or khakis. And though a person can carry one in his pocket, that isn't always a legal option. In my locale, fixed blades must be worn openly. Keeping it in your pocket, or in a neck rig under your shirt is a big no-no.
I have picked up a few small fixed blades along the way. I like to carry a puukko when I go out on a dayhike.