Trained != practiced
The trouble with having someone who knows Morse code is that learning a skill isn't enough, you have to actually use it otherwise you'll lose it. That's even more the case for something like this as an emergency backup, since it really needs to be second nature to be useful in that kind of situation. And that means constant practice of probably hours per week just for something that will probably never be used, taking time away from work and training that is much more useful.
In addition, humans are rather squishy. It's all very well to complain about unlikely events like EMP, but in the real world systems like this are far more likely to be used for boring reasons like a broken radio set. A rugged tablet stored in a secure locker is far less likely to be damaged by shooting, explosions and collisions than a human. And, indeed, as long as the locker is metal it won't be affected by an EMP either. A tablet controlled system could well be more robust and reliable than one that relies on a couple of squishy, out of practice meatbags.