Well of course it adds latency, but this is a common thing in live sound and in studio aswell to route groups in groups sometimes on multiple layers. Using extra channels to route back groups or matrices through external ins, so you can group them etc etc makes it ridiculously overcomplicated and a big waste of input channels.
So it would be nice to have the possibility atleast and then the user has the responsibility to compensate with input delays, to have perfect time alignement – for sure automatic delay compensation is something none of major companies such as DiGiCo,Avid,SSL,Studer does not have for this level of advanced group routing – it is the responsbility of the user to do that BUT you have the option for doing so.
Sadly this is a major issue when it comes to choosing console I don’t go for dLive (or Yamaha) and would be a total dealbreaker if oneday they’d decide to do it. Right now I’m about to buy a new system and was hoping for this issue to be already solved – because apart from this, Dlives are in fact great consoles.