I intentionally picked an extreme example to illustrate my point, which is that most of the ethical concerns with giving people brain implants are function of the drawbacks of currently available implantation technology; not fundamental issues with the concept itself.

Obviously we won't be getting things quite to the level of cost and safety as tattoos anytime in the near future. Even Elon Musk's goal with Neuralink is somewhat less ambitious; he only wants it to be as safe and convenient as LASIK.