It was a skill that some were very good with
The WWII signalman who taught my father morse code decided he would join a typing contest run by the towns office supply place. The first prize was one of the brand new daisy wheel typewriters. The guy brought his manual typewriter and managed to out type all the local secretaries and then tried the new electronic typewriter and it couldn't keep up with him. He would routinely communicate for hours at time in the 100+ WPM bands and he could do bursts to the limits of the equipment.