You are almost completely correct. It does have wireless charging but like your cell phone eventually the life of a rechargeable battery wears and needs to be replaced.
That you are wrong about the last part. Our latest two generations actually use ipads for the doctors and iphones for the patient. I don’t know too much about the security on them as that’s my area of knowledge. That said unlike a pacemaker our devices don’t keep people alive. They lessen movement disorders and reduce pain but people won’t die if they get turned off.