Fair question. It would be more accurate to say that you can own "mathematically guaranteed exclusive control over" bitcoins. and you that can store that math

Fair question. It would be more accurate to say that you can own "mathematically guaranteed exclusive control over" bitcoins. and you that can store that mathematical guarantee on any number of cheap, readily available physical devices. You can also elect to destroy the possibility of outside knowledge of the secret, leaving the "physical memory chip" as the sole means of humanity interacting with those coins.