Very simple, a light gauge steel frame is a high-quality product. It is light and strong: it will not burn; it is termite, borer, and fungus-proof; and it will not shrink or warp. It is environmentally responsible, low on life cycle energy usage, recyclable, and saves timber resources. The frame is between 33-50% of the weight of a comparable timber frame, with a far higher strength to weight ratio, and more than 60% lighter than a concrete building. Steel features one of the highest strengths to weight ratio of any conventional building product.
Your window and door openings will be precisely placed (or perfectly tapered depending on your design), meaning fitting will be faster and easier. Because steel doesn't warp, twist, bow, or settle, you will experience less 'nail pops' requiring rectification. You will also experience drastically reduced instances of doors and windows sticking because a steel frame never 'settles', it's engineered to maintain its dimensions for the lifespan of the building.
Steel is 100% recyclable (in its purest sense) and has a virtually infinite life span; it's the most recycled product on the planet. Termite treated timber is un-recyclable (straight to landfill) and almost all other timbers are only down-cyclable. Steel is 100% termite proof, requires $0 of termite treatment and $0 of ongoing termite maintenance. Steel is 100% non-combustible, it will not burn or 'char' and it will not contribute to a fire or the spread of fire. In a bush-fire, an ember attack to a steel house frame and roof space will not ignite the frame.