The style tokens result in pretty incredible and realistic audio.
But yet here we are, 9 years later, and the Kindle apps on Android, Windows and iOS support screen reader access to books. Those screen readers can use an array of voices, undoubtedly including the speech engines used in the original TTS feature written about here.
Most decent TTS or assistive technology systems have a pronunciation dictionary. This is a very real problem for people who use screen readers on a daily basis but luckily it's a (mostly) solved one.