Displacement in Decals

I was wondering if there is a way that I can use displacement when I am adding a decal in unreal. when I activate the tessellation attribute it still doesnt activate the world displacement option on the material node.I 've read more or else why this is natural since the decal is not an actual mesh, but I was wondering why is there a texture for displacement in quixel megascan decals for example?how can you use it?