Yeah I've heard these arguments before. If your sailboat has no electricity or just basic lights then "proper" navigation is important but I prefer GPS. Sure I've been asked what happens if it fails.
Well if my charplotter fails I guess I could rely on the laptop system that we always use. If that fails as well I guess we could use the back up laptop, if that fails the old laptop might work if I could get the TV to work as a monitor, if that fails I guess the old Gecko would have to do as we always have paper charts.
If the GPS system fails......well then I'll just stay out because clearly that would be the best place to be when that happens.