I got very excited at that link and then progressively more and more disappointed. Why do they have a slick animated ad reel with no example of the speech outpu

I got very excited at that link and then progressively more and more disappointed. Why do they have a slick animated ad reel with no example of the speech output? Why is there no example anywhere, even on YouTube? What's the point of this as a chrome extension when you can already say "ok Google, read aloud"? Maybe I'm just salty that I'll never find a good solution for my favorite ebooks that never got an audiobook version.