I know people get elective surgeries all the time (plastics, etc), but I feel hard pressed that this company is going to convince people to open up their skull for some promise of cool technology.
Even if it is successful from a technology perspective, the chicken and egg problem they'll face with developers is an order of magnitude or two higher than with AR/VR headsets. It's already an uphill battle without having to convince people to open up their brain, I just can't see this gaining any adoption unless there's a surgery-lite path outside the skull.