IME, the Coghlans waterproof fire sticks are basically indestructible. It's a fibre material impregnated with wax. It's easy to break/cut off a chunk, so one stick can make quite a lot of fires.

One of these is always in pack and pocket when I'm off road. They have taken swims in rivers and gone through the washing machine without apparent damage.

I haven't tried lighting one of these with a fire steel -- it may be necessary to fluff up a bit of the material to provide a spot for the sparks to take hold.

Would desert heat melt the wax (all over you and your gear)? Unknown. Wrapping in plastic might be prudent.