Good post! I think the best current application of GE today is saving and printing the overhead photos of ports / harbors etc where you want to sail. You can make a notebook of them prior to a cruise and use them as you pilot into a place.
I downloaded it last night and picked at random some obscure port, in this case Luderitz in Namibia (I wasn't kidding!). The features were there in the water, and I could infer the direction of the swell off the Atlantic, plus I could clearly see docks, rocks and places to avoid.
Add a "depth layer" and it would be amazing for planning, not navigation, though.