Mechanical switches are just like analog vinyl. Because the action is analog it isn't just on or off but has a slight curve between the states.
This. Exactly this. Inexperienced typists just don't get it.
To convey proper nuance in text, I don't always want exactly 1 letter "A" when I press the "A" key. Using uniform whole letters can seem jarring and mechanical, particularly when writing personal email. Sometimes a message composer only wants, say, 0.95 "A", just to soften the letter out. Other times, it's nice to smooth the letter out a bit, letting it fade out genty across the length of the word instead of being uncomfortably square.
These mechanical keyboards are usually tuned to be "warmer", as well--when you press that "A" key, it has overtones and harmonics from other vowels. A little bit of "E" goes a long way, but true "golden fingers" agree that plenty of "O" adds mellowness and roundness.
The adoption of these digital, non-mechanical keyboards is also one of the major reasons why emotion and subtext - especially related to humor - are so often lost in text-based messaging.