Every so often I look into speed reader software. I like the experience, assuming the implementation is any good. I feel the ones that just flash one word aren't as good as ones that allow you to display three. With three words, you basically see the words in context, reducing the likelihood you'll forget what you are reading.
But it isn't easy to determine what is optimal to read like that. Go and get a free book, dump the text in, and suddenly you become aware of how much text is in a book that you do not want to read, especially not ~1000wpm. No, you want long interesting texts. It is practically a meditative experience if you get something that works.
So, I think there is a use case. In fact I think there might be magic of a sort.
But I tend to abandon the project given that text needs to be pre-scanned in order to see if it is a good candidate for the RSVP reader.