Combining the touch detection with other devices would already be useful on its own. A phone and neuralink could work together and figure out when I'm holding it and unlock automatically and then lock it when I stop holding it. The connection between them would have to be trusted and secured of course - it would need to verify the unlock signal actually came from my device.

Getting something like x,y,z coordinates of your limbs relative to the device would be a good primitive for many features (same usefulness as acceleration and orientation sensors in phones). If that was fast and accurate enough, that could be used to control robotics.

Pairing with other devices and issuing gesture commands to them would be another possibility. Sign language might be translate-able directly to bytes.

We're talking about building Pong at this point. There will be lots of creative solutions found within the constraints.