its true but neither is brain stimulation which has actually been around for a long time but reserved only for people who are helped by no other treatment. If you can take a pill that works that is usually the best option.
Implants mean Brain Surgery. We make jokes "this isn't brain surgery!" well this is :)
We are talking about high risk and easily $100,000 to get an implant. So there would need to be medical breakthroughs as well.
Don't get me wrong, there are some use cases that would be very tempting but if an external system could do it I would go with that.