In my ongoing research about fire-starting materials and techniques, I recently tested the value of dry cattail heads as a tinder material.
The old seed heads dry out late in the season and can last through the winter. They stand there all brown and fluffy, tempting anyone in need of fire-making tinder to snatch it up and use it. But here's what I found.
So, what does all that mean? In my opinion, it means that cattail fluff is a useful addition to a normal tinder bundle. Because it so readily flashes into flame, it can be considered a natural "accelerant" material that might enhance the ability to ignite the rest of a tinder bundle.
But on its own, it's not much good. For tinder to do its job, it must sustain a flame long enough to ignite fine slivers of kindling. And for kindling to work, it must sustain a flame long enough to ignite the fuel wood. Cattail fluff doesn't maintain a flame long enough to be considered good tinder on its own. But, again, I would readily add it to my normal tinder bundle because of its ability to be easily provoked into flame by a small spark.
So, by all means, add cattail fluff to your tinder bundle and see if it helps with your fire starting technique.
By the way, another material that is tempting to use is dry pine needles. My experience with these is that they don't work well. In fact, it's hard to get them to burn at all. It's as if they contain a natural fire retardant.
My favorite tinder materials are dry grasses, juniper bark, or cedar bark, shredded and worked into a birdnest shape.