One could say that about all sorts of capabilities in an aircraft that, in normal operation, seems insane. Is there ever a valid reason to fly a cargo plane inverted? See https://en.m.wikipedia.org/wiki/Federal_Express_Flight_705 for the answer.
One problem with flying inverted is the bottom of the airplane tends to accumulate junk - nuts, bolts, dropped tools, lunch boxes, dead mice, etc. Turning the airplane over means all that junk falls into the machinery, potentially jamming it.
Point being, in an unforeseen emergency, allowing crews to override the normal safety mechanisms may in fact save lives.