I still have some pull-through sharpeners kicking around. I hate how they force me to choose an edge angle and chew off a bunch of steel unnecessarily -- it's a lot of work to fix it later on the grinding belt. I guess it's still better than grinding on a concrete sidewalk.
That is why a "Carbide 100" type tool is in every vehicle and emergency kit, along with industrial diamond. It lets me choose the angle and the force I apply to the cutting tool. It's still a ragged edge, but there are times when that is enough to pull you through, or bring a beater back into service. And not destroy the bevel on a better knife.
Like I said earlier, these little tools can repair all sorts of other tools. Hatchets, loppers, paramedic shears, saw blades, you name it. I personally don't assume I will have a carefully curated selection of magnificent tools when the spam hits the fan. I think this sort of "moon landing" mentality is not resilient or adaptive enough. There is steel everywhere, dull as hell but serviceable, and I want the option of making it cut.
There are many versions that are the same tech; they all look pretty much the same as this:
[Argh, multiple edits but now it works. Cheers all. :-)]