The road to perfection is paved with failure.
A failed drone is useful because it tells us what does not work, no matter how much money is thrown at it.
Some ideas are simply unworkable and therefore should be discarded at the start. The atomic airplane, for example.
Eisenhower ended a program to develop an atomic airplane based on the wise observation that a crash proof airplane is impossible because of many uncontrollable factors, like weather, to name one. Therefore all airplanes are prone to crash. Most crashes occur on takeoff and landing. And these usually take place near cities and military bases. What do you call an atomic airplane that crashes?