It depends entirely on the situation. A situation in which failure would be the overall better outcome would be when that failure opens up more doors that lead to a more definite victory. It would also be benificial to fail because you learn more from a failure than you do a success. Failure also keeps people pushing. If you have a massive victory, sure youll have some people that are motivated to keep working but a large portion of people might see that victory as a stopping point. Im sure youll say "but if you fail wont that make people give up too?", and youd be right but thats just because theyre discouraged. Its far easier to convince someone to fight who is simply discouraged than it is to convince someone who feels theyve already won.