It doesn’t burn…but vinyl burns very poorly, creating gases that tend to put out the flames. The vapors are irritating—no silent poisoning is possible, unlike carbon monoxide from burning wood, kerosene, or diesel.
Steel will dent, and is more difficult to install neatly. Damage would likely require replacement of an entire wall. Vinyl is easy to repair or replace.
The coating on steel can occasionally be scraped off. Vinyl color is through-and-through or at least molecularly bonded, not baked-on, painted, or enameled. Scratches on vinyl are hardly visible. Vinyl siding provides some insulation all by itself.
What about seamless steel siding, like seamless gutters? Once again, steel siding is harder to install perfectly. “Seamless” is not entirely seamless. It usually comes in fifty-foot rolls. A curbside shaper guided by a human is not at all comparable to roller mills controlled by computer. The half-block long roller mill can delicately shape siding without cracking or scratching the colored finish. It will create uniform pieces that will fit together perfectly during installation.
Not that we recommend steel siding, except for customer preference, or danger of wildfire. Hundreds of homes have been damaged or destroyed during the fire seasons of the last few years. We certainly want to honor your choice of materials.