Rated for safety in _that_ environment. Not necessarily another. There's more to safety than voltage or temperature rating. Eg: flexibility, brittleness, cold-fracturing, what happens if it burns etc.
Wiring has to pass specific tests appropriate to the intended environment before it's approved for that environment.
While there's a good chance that the wiring is perfectly suitable for house wiring (except for color coding), as it hasn't been been tested and approved for house wiring, it's inadvisable to use it from the perspective of code compliance, inspections etc.
Chances are that it exceeds house wiring in all respects, but is overkill, too expensive for house wiring, and the manufacturers of it didn't bother to get it approved, because nobody in their right minds would consider paying the premium for it to buy the stuff at the price they'd have to charge for it.
But, if it's not been approved, it's still a bad idea to use it.
[I've already see you make the right choice - keep a bit, and sell the rest. The above is just an clarification.]