Minecraft wiki entry for Best_biomes_for_homes, associated text: As mentioned above, beaches are good for players who want to see the ocean, but live on land, or have an above-ground base when not exploring the ocean.
If you live near a turtle nest, turtles will lay eggs, which hatch into babies that drop scute, who grow into an adult and repeat the process. Turtles will remember their nest location meaning that the same area will be the center of turtle activity permanently. Note that the player may need to set up protection for them, as undead mobs will attempt to crush turtle eggs or kill the baby turtles.
You could stumble upon a buried treasure chest without a map, but it is very unlikely. Additionally, a beach dweller would find little use for a conduit.
Sugar cane grows adjacent to water, so a beach makes a great natural farm.
A good amount of sand, or gravel if you live next to a cold biome.
Sometimes, shipwreck generate on beaches.