Was Morse code used in World War I?

Morse Code requires less transmitter power and/or a less sensitive receiver to successfully send a given signal over a given path both of which can be an advantage, for example in mobile communications. Conversely, for the same transmitter power and receiver sensitivity, a Morse Code signal may be sent successively over a longer distance or under noisier conditions, for example when "Jamming" is in use. Finally, with the technology available in WWII it was much easier to send encrypted messages with Morse Code, since voice scramblers and computers were generally unavailable. That is, all that was necessary was to encode a text message with some encryption scheme, often by hand, and send the encrypted characters otherwise "in the clear" by Morse Code.