Regarding edits: This mode control is only mentioned in passing at most in the various Unreal videos and very lightly in 4.26 documents.
For example, if you have a sequence of shots in the same level but showing the passage of time, especially using something like Ultra Sky, the number of controls and amount of time to make sure each of those parameters has been added is daunting. Also, a real problem if you start making changes for an individual shot and realize not all parameters had been added. The edit modes relieve the user of those types of issues but they’re frequently overlooked.