Hi Rob,
Having worked in IT for nearly 40 years there is one thing that is certain - it is not a question of IF hardware or software will fail but WHEN.
I know of iPads failing, overheating, and batteries running flat. It is also the case that software bugs exist. Don't get me wrong, I have AVPlan on an iPad Mini, and on my phone as a (non-legal) backup, I also have an Aera 500 in the panel, AND I also have paper charts and, of course, a compass.
You can never have too many backups, and Sod's Law says the hardware or software will fail at the most inconvenient time.
Learning to navigate from first principles using paper maps and compass as part of your initial training is beneficial, because it gives you the foundation to understand all the electronic stuff. If the electronic stuff failed you would still have the ability to track your position using map and compass, and navigate to a safe location.
Although it is very unlikely that we will have an off-airfield landing we still practice them - in the same way it is unlikely that the electronic stuff will all fail, but I still think it is good to have that knowledge as a backup, just in case.
Cheers,
Neil