@Dr. Orange
"When you move a displacement point, the UV doesn't change and the texture moves with it."
Oh, something I didn't know. So UV Lock is available in hammer 4 as well. That's cool in some way, because jackhammer's UV Lock is very useful, but the editor doesn't fully support Source at the moment. You can load a .vmf with Jackhammer (I'm not sure it's easy to do though), but many Source-only features will be unavailable, like displacements.
In fact, I started toying with displacements right after I got the SDK to work. I like this feature so much.
@Tetsu0
I know that displacements don't seal the map. You actually have to make your outdoor area in a big box with all the sides except bottom covered with sky, while the bottom side is covered with nodraw.
Although I'm a GoldSrc mapper, it's still interesting for me to read mapping tutorials for a different engine (except the UE4 ones).