Tell you what would be really cool. They could employ both!
As you explore an area, your blank map gradually fills out. Instead of it being a final map though, its more of a hand drawn "rough" map- enough to get from A to B and noting worthy landmarks but nothing detailed (and maybe for a bit of flavour, in some places wrong slightly, in scale/position etc). This way doing nothing but exploring you get something at the end of it that is pretty usable for navigation. We're adventurers right, we'd have basic cartography skills!
You could then replace these hand-drawn maps of yours with professionally produced ones, produced by a proper cartographer where everything is neat, tidy, detailed and accurate. For "professional" maps for esoteric areas, perhaps some long jolly quests could be in order so that you can find it. Lets face it, a cartographer may not have the gumption to map out Mor Dhona, but perhaps the legendary cartographer Curumbus III Jr made such a map- but it has been lost! Perhaps you could find it...
Both map camps satisfied, with some interesting flavour to boot.
Maybe in addition the player could leave messages or mark spots on their own map, and sell it, but would have to explore the area again if they do.
Even more crazy, players could leave their own treasure for other players to find; a player made mini game.
I think Zam needs to create a kickstarter and we could throw all of our ideas into one big pot and see what comes out, lol.