While it is not certainly the most humble thing to present, this proves that the use case exists, even today. Lottery is actually a nice thing to start with. Trustless blockchain technology brings us fully autonomous lottery which can not be manipulated. Every participant knows he has the same chance as everyone else. I can not imagine how stunned will people be when they realize how it's most valuable feature can improve current systems. No middlemen, no secret fees. Just you and your business untochable by others.