The old sentiment that classics are classic for a reason holds in many areas of photography. There are techniques that most — if not all — photographers should know how to do, and this one in particular, will always have applications.
There are a few rights of passage for photographers, like HDR for instance. While some of these rights of passage are trends that rarely stick around (spot color), some are highly useful techniques that will stay with you throughout your career. One of the best examples of this is long exposure.
When people think about long exposure images, their minds will typically go to some of the visual cliches like moving traffic at night or a river flowing (though I don't want to disparage these sorts of shots, they can be great!) However, long exposure techniques are also used in manual light painting, astrophotography, and a whole host of more niche uses. When it comes to landscape, I still love the effects you can create with a dark ND filter and a sizable shutter speed.
In this video, we see one of the true staples of this technique: seascapes. There are myriad ways in which you can employ long exposure in seascapes, and they can create beautiful and haunting results.