Anyone who carries one of these - how much piercing utility do you gain over, say, a spey blade?
Pretty much none, unless you've got one like my Queen trapper where they left the entire arc cutout in place instead of rounding off the sharp bit (and even then, I can't imagine you'd get much penetration at all). The spey is probably the closest in utility to the one-armed blade, having an approximately-equivalent length of straight cutting surface and reasonably similar amounts of belly at the tip. The rounded OAM blades, such as Case and Boker have released, actually serve as excellent butter/spreading knives in addition to their sharp edges.
Really, though, I think it's just an excuse for a different, pinchable blade in a traditional pattern. Plus the "unrounded" ones like the aforementioned Queen really can be snapped open simply by drawing it from a pocket and catching the "hook" on a seam. Of course, between carrying a modern and having both arms, one can definitely argue that the utility of this design is lost on me. Simply stated, I like the way it looks.
