The whole point of this is provide power for charging phone to people who don't have ready access to electric grid. This is a LOT of people and many of them want and need to communicate wirelessly. Also, cost is an important consideration, so you have to trade off efficiency of the dynamo and circuitry vs. price. This may not be the only approach and maybe not "high tech," but it is a smart answer to an important problem.

It certainly could be designed to power other devices (bike light, etc.). And could also be used in the home to power or recharge other devices or for if power grid is down - happens frequently in some parts of the world.