I think that the usefulness of the onboard processors will depend in large part on how good a job Roccat does at making their SDK both powerful and easy to use. Having a device that can run macros/scripts in onboard hardware has its advantages over software-based input task automation, in responsiveness, compatibility, and at getting around attempts by other software to limit the user's automation capabilities-- but if the software places arbitrary limits on what the device can do with its features, or isn't friendly enough to be taken full advantage of by non-programmers, those advantages could easily wind up minimized.
Also, I don't see any mention of any sort of feature to integrate the mouse into the keyboard's capabilities, either with a USB filter or some sort of non-pass-through port on the keyboard itself-- without some sort of integration between mouse and keyboard, the range of triggering options for macros will be deeply limited, as well as losing the ability to modify outputs from the existing mouse (as opposed to the keyboard pretending to be another mouse, which it should have no problem doing either way unless the design is really stupid). So that's another area of uncertainty for how useful they'll be able to make the ARMs.
