I am assuming you are talking about wind produced waves in the water, mostly the ocean. Currently, they are used for mostly recreation only in the real world. Swimmers and surfers play in them. Some fishing and animal feeding is based on wave motion and the tides. But by and large recreation is our only real use of them.
Personally, I would really like to see wave power harnessed for creating electricity. Unlike wind and solar, wave power is literally constant day and night and with relative certainty with regard to location and direction of motion. If we could harness this constant natural motion to power an electrical turbine, electricity could be produced to service many coastal areas of the US. And coastal areas tend to be heavily populated, an added benefit. Researchers are working on this potential real life application of waves right now.