It looks as if Ovi Maps includes just the images and not the index of streets and stuff. So, at minimum, Ovi Maps is hitting the server for search suggestions, for the latest maps (if they changed by some off chance), and for the coordinate to show on the map.

Until it is possible to use Ovi Maps completely offline (minus hitting the servers for traffic information), I question its usefulness compared to my Garmin Nuvi 265WT.