Such claims need to be tested scientifically. There is no way to test this for yourself and actually come to useful conclusion. Any effect of such a change, positive or negative, will be subtle and there is no way to assess the difference yourself. You will be “primed” to perceive the supposedly improved text as better and possibly come to that conclusion just because of this priming. That’s why science uses double-blind tests, where you don’t know what is actually being tested.
And reading speed isn’t reading comprehension. Even if the method would actually make you faster, it doesn’t mean you actually understand the text just as well as when you would read a normal text.
There are also confounding variables, like the font weight. The website shows a very light text and then the “bionic” text with some letters being bold(er). Maybe the problem with the light text is that it is just too light and the reading improvement comes from the bolder letters – not their “bionic” distribution. Such things must be taken into account and tested for.
And from my experience with reading research, the entire premise is highly questionable. The focus points we use while reading depend on many things:
personal reading experience
personal understanding of the specific sentence you are reading
the text layout (typeface, length of line …)
the reading conditions (reading distance, lighting …)
This “bionic” approach tries to force focus points on all readers of a text, independent of their reading experience and how good they understand the text. I don’t see how that can work. If the focus points don’t match what one personally needs, there can’t be a positive effect and it is actually more likely to see a negative effect caused by forcing focus points in the wrong locations.
But I guess the makers of that product don’t really care as long as they can sell their API access. If they would care, they would have started with proper scientific testing, not with sensational claims distributed through general media outlets.