A friend (now deceased) from church was a former railroad telegrapher and he once told me that he could often identify a sender based upon his fist. To me that seems amazing, akin to identifying someone based upon their handwriting.
That’s true of non-modern keys and internal keyers, which today automatically provide perfectly even spacing. With modern equipment, aside from
speed selection, (Words Per Minute) everyone sounds exactly alike.
Many will still operate what’s called a
straight key or bug or cootie in which the duration of each
dit or dah can be left to the
style of the individual sender -Your friend is 100 percent correct.
I was an Army radioman. The skill later became a hobby. There is a benefit to sending Morse in the antiquated way, and that is that you can
tap out messages by feel.
With the deafening noise of battlefields, abandon all hope if you must rely on hearing your side tone.
The military has discontinued the use of Morse. However, commercial pilots still know Morse because beacons continually broadcast in Morse to identify their location.