you need *very* thin and *very* long wire to make an effective filament. Tungsten is actually pretty damn conductive--nowhere near copper, but significantly more conductive than the brass used for switch contacts and connectors. The reason it's used in light bulbs is not because of its resistivity (otherwise we'd be using nichrome), but because it has an incredibly high melting point--very few things can get hotter than tungsten without melting
-F