You have to strike it vigorously with something sharp to get sparks. It's not inconceivable I guess, but it's hard to imagine it happening. That's one thing to keep in mind, as well- you do need something to strike it with. A knife is great if the spine is sharp. Probably a multitool would have something. It needn't be steel but it does have to be hard and sharp.

You could easily keep that little toggle on a keychain or in anything with laces. One thing I should mention is that if you use it enough to wear all the coating off then you have to be mindful that it doesn't corrode. Not that it's a huge issue, just something to keep an eye on.

I'm a big fan of Ron's firesteels. I have at least a dozen, probably more. Recently I bought 3 of the toggles, two plain ones and one of the magnesium ones with a 'steel glued to it. They're not as easy to strike as a longer one would be but they do put out good sparks. Probably my overall favorite one for hiking and camping is the GobSpark Armageddon FireSteel with the Super Palm striker. The 'steel snaps right into the striker, protecting the rod and giving you a striker that fills the hands and makes lighting easy with winter gloves on. Right now I have three in red and one in black. No affiliation to the company, I'm just a deleriously satisfied customer. So few products give you much more than your money's worth, but these are one of them.