I think the study of cortical implants is interesting for this question because they touch the same questions basically. Cortical implants basically form the o

I think the study of cortical implants is interesting for this question because they touch the same questions basically. Cortical implants basically form the opposite side by providing a direct interface between machines and the brain. They are already available and deployed in medical contexts. Why aren't they deployed in healthy people as well? They have pretty cool advantages. With them, you can listen to music, etc. without being affected by outside noises (unless you want to). Imagine having a phone call in a noisy environment and you can actually hear stuff. Imagine your neighbours having a loud party but you can still sleep tight because you turned it into sleep mode where only fire alarms may disturb you. How many conflicts you could avoid! However, cortical implants have heavy disadvantages: They give you worse hearing quality than normal hearing, they require surgery, and also need devices on the outside that are in contact with them. That's why they aren't useful for healthy humans yet. But maybe, with improvement, one day they will become. Basically, the problems of this technology will be the same: worse quality, requirement for surgery, requirement for extra devices to carry around.