I mostly-edc a Gine Ingram Lacer...nice little knife, sits flat in the pocket.
The leather on mine is a very dark brown now.
I carry a fixed blade for a couple of reasons:
1) very comfortable to use
2) no particular reason not to
3) looks nice
4) works good
I don't have any particular thoughts about using it as a defensive tool. I certainly would if I had to but I have no training with edged weapons.
On the other hand, I was given my first knife when I was seven and I have spent my entire life carrying, maintaining, and on occasion building, knives. So anything I have on me is very, very sharp, and I am pretty good at handling them safely and efficiently. I would be fairly confident in my ability to treat a knife as a defensive weapon in most cases. I do have a fair amount of empty hand training.
But I would be the first person to comment that the knife I carry would not be a good choice for defensive use. That is not at all a priority for me in knife selection. I just like to have a good utilitarian cutter that looks halfway decent if I produce it in a restaurant to cut a steak.