It does not tell much that is useful. All it tells you is that it can survive driving a 1 ohm load for a short period of time.
It it suggests is that its protection might actually be inadequate. Since 1 ohm is an unreasonable load, it ought really to shut down, as a load like that won't do any amplifier any good.
But, if the amplifier is designed to handle that load, it shouldn't harm it. Sure, eggs can be fried on top of it, but if the heat sinking is at least adequate or it has fans, what's the problem?
If you look into amplifiers and other electronics used for sirens in fire alarm systems, they're required to operate to the point of destruction in the event that the place is actually burning and in conduit, the speaker wire's insulation can melt, causing a short. Obviously, if the conductors are both shorting to the metallic conduit, the speakers won't receive anything, but the amplifier will survive- this kind of equipment is considered 'life safety', rather than the equipment we use, which is considered 'lifestyle' by the electronics industry.
I think it was more than ten years ago, but an extremely argumentative former AH member was here for a short time- he insisted that his way was the only way and had worked for companies that made life safety equipment.
While life safety durability isn't needed for our purposes, it sure makes amplifiers robust.
OTOH, even an arc welder has a specified duty cycle.