I agree, I think it's mostly about routing that is highly recommended for cyclist due to road conditions and amenities that are in the area as you travel. The amenities may not always be accurate but at least you know your coming into an area that has something. And really the only time road conditions change is due to construction and that can happen driving a car and happen without foreknowledge. That's life.

But I would rather rely on those maps then a specialized cycling related GPS. I can't figure out why a company that builds a bike GPS has to charge $500 to $600 for it when I can get one for a car for less then $100! Sure they have to use a longer lasting battery but that battery isn't even closely worth another $400 to $500, more like another $25 plus add another $5 to seal it against moisture and you have a bike GPS for under $150. Besides there have been thousands of bicycle tourists that have traveled the world without any GPS, just a map and talking to locals.