I had a RFID chip implanted in my hand 3 years ago, just for self-interest. ( I have no desire to enslave the human population in end-times )
It was inserted by a friend who's a registered nurse, with some Lanacane. (highly recommend the Lanacane!)
I chose my non-dominant hand in case something went horribly wrong, but there haven't been any complications.
It is very convenient and I use it daily. My house door locks, garage door opener, car door locks and safe are all accessible by a swipe of my hand, as well as a rfid reader by my bed that turns off all my house lights and lowers the house temperature for overnight.
I can understand the concerns people have about implanting chips - chipped bracelets/rings could all do the same thing and I haven't been able to convince my girlfriend to get one implanted yet -- but I just love the convenience of always having it with me.
Sadly, my workplace won't let me use my chip with their swipe access system. Which would have been super handy today, since I forgot my ID card, and had to walk around to the front entrance in the pouring rain.