That seems pretty harsh.
I have some friends cruising out of the UK that were in Maine. They were very comfortable with their electronic charting. I think people that are comfortable, don't worry about losing the ships power. They have redundant devices. These folks each had a laptop, a spare(from an upgrade), a small tablet, smart phone with a chart app, onboard Chart plotter and maybe a hand held gps with simple charts.
At any rate, with solar and wind generation onboard, they were covered if something catastrophic happened to the ships wiring.
The gear they had, laptops, smart phone, tablet, isn't too unusual these days. You could find it in a family kitchen.
But for boats that are comfortable with electronic charting as their sole means of navigation, they would not put that trust in one single system or onboard source, they would have several redundant unattached devices.
Not everyone accepts their way, but I know their seamanship is top notch!
I am sorry it came across harsh, but as I said above, it is something I feel very strongly about.
I have a friend back in St Pete who does not have a single piece of electronics aboard (not even an air conditioner!!) and only steers by paper. He is a long time advocate of celestial navigation. He has crossed the pacific with his family and shuns most modern devices. That does not make his way the best way either.
Let me expound on my story. In circa 2001 we took a lightning strike. It did not hit us, it hit many boats down (an important point, btw). We had two chart plotters - one at the helm and one down below at the nav station. I also had a backup handheld down below (the old Garmin 76? I think it was, remember those, the old black and white thing?). Anyways, the unit at the helm never turned on again. Obviously it was from the lightning strike. THe unit down below powered up fine. I replaced the unit above and everything seemed to work perfectly. Not long after, we took off for the Tortugas. In the middle of the night the old unit locked up. It wouldn't scroll or do anything. We couldn't even get it to power off without tripping the breaker. Luckily, we had the handheld as a backup (the Garmin). It would power up but it would not get a fix. It never worked right again. As it would turn out, after fully rebooting the system on a forced reboot, we got the CP's back up and running and we were fine. But the CP down below was always locking up and acting screwy. Raytheon sent out their techs and finally concluded the unit down below was also the result of lightning... which was NOT apparent at first, as I explained. I suspect that was the same thing that took out my handheld and why it never worked right again.
In 2010, while crossing the gulf, I looked up in the middle of the night and saw that I was running 44 knots. While I realize that I have a fast boat, I am not quite that fast! I looked at the chart plotter and it had me squarely on some parcel of land somewhere in Florida and moments later, my autopilot did an abrupt 180 in the middle of the ocean. We rebooted the system and it came back up fine. I had that problem several times afterwards, and think I finally traced the failure down to corrosion on the HSB to the autopilot. At least, I hope that is it! But a word of warning, when you have all your stuff connected together, a failure on one can lead to a failure of everything.
SO the morale of this story is that I have been burned. I came out of them ok, but I might not have. Electronics will fail eventually. They all will. I believe prudent seamanship is to use as many things at your disposal as possible (within reason) to maintain the safety of your boat and crew. That includes paper charts which do not run on batteries or get hurt by lightning strikes and it includes electronic charting tools which overlay exact positions consistently. There is no reason to rely completely on one or the other that I can comprehend.
Those are my opinions and that is how I run my boat. How others run their boat is of course their prerogative. They may have a different tolerance for risk than I am comfortable with. But I personally would never make a passage on anyone's boat with them if they did not have paper backups and do paper plotting (at the very least consistent positional logging). Experience has taught me otherwise. My guess is that those who rely solely on electronics haven't had that lesson yet. I hope they never do.