Any advantages this would have over a computer without an internet connection?
It is easier to tell what a typist is typing from their audio signature than it is to TEMPEST a monitor, especially now with modern EMC requirements cutting down the usable signal.
Some people used to have "low emission fonts"; fuzzy edges in very low contrast.
Anyone care to process this clip? I might even have the 'plain text' around somewhere.
On a serious note; I used to get about 5 carbons max on a mechanical office typewriter years go using 'onion skin' paper.
Photocopiers mostly use scanners these days? Back to square one?
Any attempts at picking up audio|electronic emanations will be foiled by traditional TEMPEST type protection.
Typewriter ribbons can be dealt with by old fashioned incineration.
The only way to acquire a signal would be by infiltration of the facility housing the targeted systems.
However there is one problem with typewriters people generally forget: you can extract everything that has been typed from used typewriter ribbons...
A cloth ribbon would be hard to extract anything from, I'd think, maybe you could with a brand new one. Carbon film ribbons as used in the Selectric yes, you can easily read them but they can be shredded or burned to dispose of them securely.