Possible application for topologies

Most of my students asked me: “why do we need this or that!?”. In fact: for topologies I failed in answering often. One possibility of usage is shown here:

In fact I was confronted with this problem more then once: two neighbouring polygons, move one, move the other and hope that snapping will do the rest. Using the topology tools in ArcGIS makes this much easier as it treats your shared vertexes as one vertex and adjust the geometry of both polygons… “Thumbs Up!” for that!
Find more informations on topology here: LINK