Earlier quoted context omitted.
Two kinds of people will buy them: enthusiasts and people suffering from chronic conditions with nowhere else to turn. Similarly, you can buy unapproved, unresearched medication on the internet. You take on the risk. Personally I like the idea that people can take their lives in their own hands. As long as it's clear that they're opting out of the guiderails put into place for those of us who are more cautious.
If we were a lot better about not letting your teens and twenties so heavily define your story arc as a human, maybe. But without some sort of insurance and/or escrow program any implant than gives you any kind of edge will be accepted by people too young to really understand the consequences. Especially the sorts of people who think they'll dead by 30 so side effects that show up in your 40's are no big deal.
This seems sorta like not letting 80 year olds have email because they don't understand it and might get scammed.