I'd keep the second key and use it as a backspace.

(scratch that.. some googling shows there is a backspace in morse - it's "........")

Is Morse Code nore efficient than ASCII?

Yes, if you consider there are codes for commen phrases i.e 73 for "best regards".

https://en.m.wikipedia.org/wiki/Morse_code_abbreviations#Tab...

If I'm understanding this project correctly, it requires that you type the binary code for the ASCII character. E.g. for A, you need at least 8 keypresses for 01000001. In Morse, you would need two: .- (short-long).