While ample instrumentation exists in the cockpit to provide ETA's, fuel burns, and other information relevant to the flight (such as equal time points, times to alternates or diversionary locations, etc), we still calculate it by hand to make sure what we're seeing on the instrumentation is correct. We're required to do so. Being constantly in the loop this way means there's not a lot of extra work to do in the event of a failure of a long range navigation system...and it has happened. It also provides an accurate navigation log on paper when we're done, which goes into the trip kit and gets retained at the company along with all the other paperwork associated with the flight.
It's one thing to go from A to B for hours and make an occasional glance at a FMS readout and a multi function display with a moving map. It's another to be completely in the loop and aware of your position at all times because you're constantly following along on the map, recaculating your distances and speeds, and ensuring that you're really where the airplane thinks you are.
I fully agree, and when delivering piston pounding airplanes trans oceanic we also use Sat phones as a backup for the HF and relays through airliners flying above us......and of course I always have my closest alternate ready for an immediate turn if needed.
I find the Sahara desert is more demanding than the oceans though especially during the Harmattan season.