Hmm, I have a mouse and trackballs from ploopy, they run QMK, so why was a new project needed? What is the added value?

To me, the missing feature in the QMK ecosystem is a devices too device communication channel. For now there is only caps lock & others: it would be nice to activate a mouse layer (for instance: increase DPI) to a keyboard key.

It is probably solvable if a heavyweight was to push for new HID descriptors or something similar.