You can only offer such an interface with FPGA, first class drivers, TotalmixFX, DIGIcheck, headphone output, at such a low price if you don't implement some features, e.g. FX chip, stand-alone operation, Class Compliant mode ...
The Digiface USB already offers some special features like four ADAT ports, which can all be switched to SPDIF protocol if needed.

But I think it is a good hint to give this device at least Class Compliant mode, even if it should cost a few Euro more, so it can be used more flexible.

That would mean then also more prospective customers / buyers, if one could connect it to Apple IOS devices or also Linux.
If you then want to record with an iPAD, then you can easily connect your most beautiful preamps via ADAT up to 192 kHz even without these preamps have CC mode, which is a great feature of the Octamic XTC. But it is not available at the moment and the 12Mic has no CC mode for USB implemented as far as I remember. Is a pure management interface for firmware upgrades.

I think that would make sense if you could then use the Digiface as "universal adapter" for all possible preamps and ADDA converter, which themselves have no USB CC mode to be connected to IOS devices or Linux.
And that would include not only RME devices, but also others.
Which would basically lead to even more potential buyers.

So lets hear whether RME likes that idea or whether it could be possible to implement now or for a later generation of Digiface USB, if the FPGA should be full ...