I think displacement maps are not that frequently used in game graphics these days. The typical thing is regular geometry with normal maps. However, triangle so

I think displacement maps are not that frequently used in game graphics these days. The typical thing is regular geometry with normal maps. However, triangle soup is very difficult to modify in any way. The cool thing about displacement maps is that they can downsampled trivially, so if you're doing runtime tesselation you can get smooth LOD scaling (at least down to your base mesh) which is nice. Less usefully, they can also be tiled, blended, interpolated, scrolled, animated, etc. On the other hand, UE5's Nanite achieves the same LOD scaling but far better, without the limitation of not being able to scale down past the base mesh and with a built-in workaround for the issues GPUs have with small triangles. It's possible that people might use displacement maps in the authoring process, which can then be baked into static meshes for Nanite. Then it would just be a convenient-ish way for artists to author and distribute complex materials.