The Litchi app is very powerful, way beyond what DJI provides, just to claim they have waypoint navigation. Autopilot is good too, but more difficult to understand and remember how to use. Litchi seems more intuitive.
Using the online Litchi MISSION HUB, their app provides you with ASL elevations for anywhere in the US, as well as doing the math to tell you how high you are in relation to your first waypoint. Others don't. This is very useful to plot your course, then later upload to your device, to execute later. Each waypoint lets you point the camera at a POI of any location or height. You can also download missions that others have created and then make your own changes and fly the similar mission yourself. Most of all, the Litchi mission can run 100% autonomous, beyond the range of your RC and continue the mission on it's own until it returns to radio range to view the video feed. This helps if you need to go behind a hill, around a tall building, or simply beyond the radio range of your RC. And since the P4 RC is the weakest Lightbridge radio DJI has manufacture to date (GL300C), the Litchi program comes in handy for missions that are more than a mile away. The accuracy is really good, however it takes a while to gain confidence. Avoiding power lines and other wire is key when flying low, you never want to fly a mission without scouting the entire route first if you plot a flight under 100' AGL.