It's always better to use the right tool for the job. The improvised ones are just that, improvised field expedients, second or third best. Their saving grace is that they are there at hand when you need them. Of course a gun or a sword or a spear would be better. These are simply somewhat better than nothing. And they beat the hell out of screaming for help.
The exceptions are the tools you use every day. If you are a carpenter you already have perfect body mechanics with that roofing hammer. A cook? Nobody has **** to teach you about how to use a knife.
To answer your other question, I've trained with a lot of weapons including some pretty unconvenctional ones. I'm reasonably confident that I could make the expedient ones work pretty well. But a lot of people haven't and are just kind of hoping that it would magically work out. Take the classic keys between the fingers. Have any of the people who talk about that tried it on something approximating a real target? How badly torn up were their hand afterwards. Could any of them hit with any real impact and have the keys stay more or less straight? Not one in a thousand who says he would rely on that has actually practiced it even once?
The exceptions are the tools you use every day. If you are a carpenter you already have perfect body mechanics with that roofing hammer. A cook? Nobody has **** to teach you about how to use a knife.
To answer your other question, I've trained with a lot of weapons including some pretty unconvenctional ones. I'm reasonably confident that I could make the expedient ones work pretty well. But a lot of people haven't and are just kind of hoping that it would magically work out. Take the classic keys between the fingers. Have any of the people who talk about that tried it on something approximating a real target? How badly torn up were their hand afterwards. Could any of them hit with any real impact and have the keys stay more or less straight? Not one in a thousand who says he would rely on that has actually practiced it even once?