If you have ever attempted to make a fire while suffering from hypothermia you can appreciate why I personally choose to carry this and why it makes sense to keep it protected from damage while adventuring. 

The two parts fit quite tightly, I put them together ~10% then pull them apart, repeat 5 times, then iterate the sequence each additional 10% until you feel comfortable with the fit. 

I am sure others would take a different approach to this design but I focused on minimizing the pack space used to achieve the task.