I asked John Varley about this directly, but he says he forgot.
In his 1986 short "The Unprocessed Word", he cites three other authors whose work in longhand and/or typewriter proves that you don't need a word processor. These are: SK in Maine, SR in Halifax, and DT in Oakland.
SK is Stephen King, SR is Spider Robinson, and neither I nor Varley know who "DT" is. Anyone have a guess?