The idea of typing 500+ words a minute sounds silly to me. If you're writing in a natural language and you can touch type reasonably well, your typing skill is

The idea of typing 500+ words a minute sounds silly to me. If you're writing in a natural language and you can touch type reasonably well, your typing skill is not going to be the bottleneck. Your speed at putting things into words is. Stenography or other data entry are an exception, of course, but I'm guessing the intended audience for these pitches is the average joe who dreams of writing an email in seconds.