I'm not agree, because sometimes car is already tuned and customer wants to add DPF, EGR etc.
It was not quite so long ago, Porsche EDC17CP44 3.0TDI was tuned + DPF + EGR by someone for 1200eu.
CMD doesn't read it, only VR. The client would like to know what for he paid 1200eu. The reason he asked me to check it was EGR's DTC and no gain.
So I downloaded ori file from CMD server, tuned it and wrote back... and the client is happy now, but what if he wouldn't? I can write back only stock file. And this is a really big problem.

Because there is in most cases no point to read any VAG ECU.
Take the VAG flash db and unpack the frf/sgo, job done.

I don't even read ME7/EDC15/EDC16, never mind the newer ones. There is simply no point to do so.