Like the telephone wires seen today, back in the day, companies invested in thousands of miles of communication wires throughout the US. This made them able to communicate with other states before voice communication was available. read more
The reason we hold the key instead of tapping it (like you often see in movies, where actors have no idea what they're doing) is that the actual distance travelled by the key is very small, so always touching it means always controlling it. In other words, it helps with speed. read more
Morse Code could travel over 100 miles and even farther using smoke or light at night while at sea. That was the big advantage Morse code had over voice. I will not go into the history of Morse Code. read more