This is false though. The add-on boards are miniature versions with obvious differences looking at the PCB boards.
Of course the PCBs are different but they do use the same chips and technology to generate the sound, which is what I meant by “essentially”. The external Modis have more options of course, like S/PDIF and optical inputs, that the card does not. There may be some small sonic advantages as well, thanks to them having their own shielded enclosure and own separate power supply.