This functionality is necessary to perform the equivalent of shared edits (the equivalent of a map topology shared edit in the front end ArcGIS Pro application), but in an automated way behind the scenes for bulk updating for example. So if a polygon vertex is moved then corresponding lines and points that are spatially coincident are also moved. There can be any number of spatially coincident feature classes that might need to be automatically moved.
It would be very beneficial for us to have this functionality in the ArcGIS Pro SDK.
Also documented here
Add equivalent classes to ArcObject interfaces (IMapTopology, ITopologyGraph, ITopologyEdge, ITopologyNode) in ArcGis Pro Sdk.