Amateur Typist?

In Perjury, Allen Weinstein's book about the Hiss-Chambers affair, there is an excerpt from Alger Hiss's December 4, 1948 statement to the FBI about the typewriters that he and his wife owned in the late 1930s:

During the period from 1936 to sometime after 1938, we had a typewriter in our home in Washington. This was an old-fashioned machine, possibly an Underwood, but I am not at all certain regarding the make. Mrs. Hiss, who is not a typist, used this machine somewhat as an amateur typist, but I never recall having used it.

Hiss was wrong: the machine was a Woodstock, not an Underwood, and his conflicting and obfuscatory statements about the typewriters he owned and used during this period eventually became some of the principal incriminating evidence in his perjury trials. More about that when I actually finish reading the book; but what I was struck by in this passage was Hiss's phrase "amateur typist." Can you imagine a time when those who typed could be divided into those who did so professionally and those who did so as a hobby?

I was also struck that typewriter forensic science had advanced to such a point in the 1940s that it was possible to identify not only the typewriter a particular document was typed on but to identify who typed it.