After reading the entire thread I realize that I am certainly the minority who thinks fire steels are over-rated.
I take a refillable butane lighter and a sealed gas lighter. The gas works when wet, cold, high altitude, when stomped on, when dropped from a cliff and even when consumed and expelled by a mother grizzly bear. The butane works the remaining 99.9% of the time. Sometimes use a fire steel for fun. IMHO there is no realistic situation where a fire steel can beat a butane/gas lighter combo.
I see why people use them as backup, I mean why the hell not? I myself have them in various kits, but if your with a group of 5 people all who have two better ways of making a fire, you need to ask yourself how much backup you really need.
The main downside I see with fire steels, the downside some people seem to ignore is the fact the require two uninjured hands to work efficiently. I know the blast match and others act as exceptions and that there are one hand options but have you ever actually tried them with a broken arm? Personally I see a broken arm as much more likely then your lighters failing.
Just my opinion... don't bite my head off.