I short: No.

Long answer:

Maemo mapper does not include maps, nor routing software. It downloads maps and routes from public internet providers (maps from google, yahoo, openstreet,... routes from google). So it requires an internet connection.

If you have an internet connection while on route, the map downloading can occur in real-time and on-demand. That is, maemo mapper shows you the map of the area in which you are located, obtaining your location from the GPS, and updating the maps as you move. You can choose the internet provider for the maps, and thus you can see the "Google maps" view, "Yahoo maps", etc. Even the satellite photos are available (and it is amazing to see in real time the arial photo of the area you are travelling). You can choose any zoom level, but note that the maps being used are bitmaps, not vector, so you have to choose (through configuration options) how to perform the zoom for each zoom level: by downloading new maps for the new zoom level or by resampling and resizing the maps from other zoom levels.

You can ask maemo mapper to compute the route between two places. It does it by asking google, and then it plots the route on your map. In combination with GPS, it shows you on-screen the driving instruction, when you are approaching to a "instruction point". If you have flite installed, a text-to-speech software, you can even have these instructions read aloud (altough the sound is not as clear as with Wayfinder).

If you don't have internet on route, you have to download all these maps in advance, but it is possible and easy. You can also download some routes in advance, but if you want to compute a new route while traveling, you'll need an internet connection.

Maemo mapper is an amazing application, and I use it a lot (specially after my Wayfinder demo license expired :-)), but it is not a proper GPS navigator. It cannot recalculate automatically the route if you miss an exit, or if a road is not accesible. You have to manually perform a new route search (and you require an internet connection to do so). In my opinion, maemo mapper is not a copilot which can guide you to your destination, as Wayfinder can do. It is more like a tool for your (human) copilot, such as a road map on steroids, and with gps support.

On the other side, maemo mapper has features not present in Wayfinder. For example, you can record the track of your travel (i.e. where you were at each time). This track is stored in an stardard format, and you should be able to find tools for extracting information from it, such as total distance travelled, average speed, and so on. Another nice application, if you took photos during your travel, is to match the timestamp of each photo agaist the track, so you can have all your photos geolocated in seconds.