You can change the salt into an Energy. If you put salt water in the metal plate it helps the plate collect the energy. And people can use it! With a small plate, it will be hard to move big things such as vehicles. But when you put a lot bigger metal plate, it is easy to move a sports car. Salt Energy can let the sports car go 337.6 km in an hour with it!
Also, with salt water, you can help poor countries. If people in poor countries need some electricity, they have to work for hours and hours only for a light. But, if you use salt water, you can use the lights, and use electric home products.