Cooking a la plancha is a rustic preparation. The seasoned surface and high heat mean the ingredients need no enhancements, allowing the flavors of the food to shine through. For this reason, it's best to make sure you choose the freshest ingredients available. It is also a very low-fat and healthy way to cook.
In essence, recipes that require a blast of high heat are ideal for the plancha. Cooking slower is also possible on the plancha however the benefit here is not so much in the cooking process but economy.
A la plancha is often used to cook seafood. It's the ideal method since seafood is often best with quick, high-heat cooking. In Spain, you can often find planchas set up right next to the docks and ready to immediately cook up the daily catch.
Make sure that your plancha has a lip to the edge because this stops oils and juices dripping off the plancha and onto the coals. For commercial cuisine a la plancha (or just cooking large quantities) then a plancha with a drip hole and removable waste container is helpful. Here's one made specially for a kamado ceramic grill.