The Tested website wrote a well documented article “In Praise of the Mechanical Typewriter“, quoting a typewriter fan:
A typewriter is a single purpose machine. The only thing it’s good for is writing. Computers and smart phones are not single purpose machines. With a typewriter, your mental focus on that page.
But what the article does not mention, is the fact that secret services in several countries are buying mechanical typewriters in order to avoid digital surveillance on (part of) their communications. Back to the future, anyone?