Just saying to check for whatever brand you're using... Didja know that Vector 5x contains a bit over 10% propane? Not saying it's not safe.. this particular one.. but it helps to know what you're working with.
I agree, you should always stay aware.
Yup, knew that, and they're not the only ones (I'm guessing your getting around to reading some MSDSs?). That's to cover the low temperature/no pressure problem. Being lighter (more like Natural Gas) it stays a vapor longer (so you can light your lighter....) although doesn't contain as much heat. They do exactly the same thing with domestic gas. The colder your winters, the more Propane in there and the less heat per fill up (same truck).
Also, you'll find being lighter, Propane is even a less problematic gas to have around in small amounts.
Again, think about it, if there was a health risk the cops would be scaring the shit out of parents with it to get them to rein in huffing and the match makers would be advertising far and wide while Bic collectively pulled their hair out. "Our matches don't emit toxic fumes like...." would be a mighty attractive advert....
But, yes, excellent point, get informed. Put your efforts in where they'll have the most effect.
OF