Keep track of what you have collected, work out the shortest way round what is left, and hand the next stop to the app that gets you there.
Keep track of Stamp Rally progress and map out efficient paths between locations, so a day out collects the most stamps for the least walking.
Get guided directions for nearby Routes, ranked by how far away they actually start rather than where they happen to be listed.
Find and store local PokéStop and raid hotspots, so the place that was worth the trip last month is still one tap away next month.
A rally is a named list of stops. Routom holds the list, remembers which ones you have already collected, and works out a sensible order for the rest — the shortest way round, rather than the order somebody happened to write them in.
Then it gets out of the way. Routom is the planning and the scorecard; your phone does the navigating.
Routes export as plain GPX, the format your watch, your mapping app and your running app all understand. Nothing is locked inside Routom — a route you plan here is a file you can take anywhere.
Progress is kept per account, so running more than one trainer through the same rally does not mean keeping track on paper.