I hesitated before posting this question because I thought many people might take it like you did. I'm happy to see that it's only 'throwawayReply', while others are being friendly and constructive :)
As I mentioned, I have no direct need to improve my typing speed. I find the fact that billions of humans sit in front of keyboards for many hours every day quite interesting. We've seen huge changes and improvements in text-entry over the last century, and it's one of history's little quirks that most of us still use a keyboard that was invented for typewriters. I'm interested in hearing other people's experiences, so I posted here to ask. If you're not interested in the topic, why did you take the time to click on the title (which is pretty self explanatory) and leave the disparaging comment? If you don't like this kind of content on HN (and think it "sounds a bit silly", downvote and move along :)
I have occasionally found that after having a sudden idea, sometimes in the heat of debate, that my fingers can't keep up with my brain. But yes, of course most of the time is still spent with my fingers poised while my brain works out what to type, and my primary motivation here is curiosity rather than desire for further efficiency.