Most of the lands in my last game were bronze-age. The Dwarves had access to Iron and Steel, though.
Why bother? Iron helps against the fae, of course, but I also introduced Tetanus. Aka every iron / steel weapon had a chance of inflicting a disease.
http://en.wikipedia.org/wiki/Tetanus
(I know, rust doesn’t cause tetanus, but it aids the bacteria and was considered to be the source for a while. I have ‘miasma’ in my games too.)
I have a god in one of my settings that’s 50% tetanus & 50% hemlock.