I wonder if they could be used as a pencil lead sharpener : )
Wire nuts are as rare as 4-leafed clovers in the UK. I've only seen them once, when Amazon supplied a couple within a box of parts to connect a Ring doorbell. I binned them, because I had zero experience with them. They look pretty strange to people who have never seen them before, as if they cannot possibly function : ) They are a successful product in North America etc., so I know they must function, but they still look odd, takes some getting used-to.
The wire nut has a spring inside that you screw onto the twisted wire. It does a good job of accommodating different twist geometries and the spring is made of strong enough wire that you can twist it on tightly. It acts like a multi-layer noose that gets tighter as you twist, ending up with continuous force squeezing the twisted wires with even more conductive wire, and it won't spontaneously loosen off. The plastic thimble provides grip to twist and insulation for the joint.
