Steel does not rot, warp,split, sag, or swell. Steel is non-combustible and does not contribute fuel to a fire. Steel does not contain the flammable, toxic chemicals that wood requires for pressure-treatment.
Steel is insusceptible to termites.
Steel can resist greater hurricane and earthquake forces. Steel can be recycled. Steel framed houses are less costly for fire hazard insurance. Steel framed houses, apartments, etc are less expensive to heat and cool. Steel framed structures typically require less maintenance.