If you can’t go back and read what you just wrote, it results in a concision of thought - formulate a sentence in your mind, transcribe. Repeat.

When you can read back what you’re writing, it lends much more scope for punning, for long, tangential sentences - as the paper becomes your short term memory.

This holds particularly true for a not only blind but aging mind, with a slowly diminishing capacity for short-term recall.

So, did the typewriter turn him into a machine-man? No. His blindness mandated a modification to his mode of expression, and the transcription technology he chose.

I can’t help but think of the allegory of the tightrope walker and the jester, reading this.