Thats not true. It reclocks the signal and sends the data with precise clock to the COAX out / DAC
Yes, it sends a clean Coax signal out, because it does not recieve the clock signal from the Pi, but from a clock on the board (the big silver thing). It recovers the clock signal and generates clean i2s clock signals with the needed frequency for the datatransfer from the Pi (Digione is clock master and Pi clock slave). So it already recieves a clean signal from the Pi and does not need to reclock the i2s signal as the Kali does.
I have seen that they write on their website the Digione does dual reclocking. But technical there is no need for reclocking of the i2s signal (as the Kali does) with the Pi as clock slave. It's even better this way, because you only have one clock domain and not two with a buffer in between wich can under- or overflow, if one clock is faster.
I think they state it does reclocking, so they don't have to explain why it is now possible to get a clean i2s signal from the Pi this easy, while you needed the Kali before. Technicaly it's different. But the result is a clean i2s signal in both cases.