I don’t have any implants installed yet, but I’ve been following the scene for a little while. I think a crucial thing to note is that the tech you’re putting in your body isn’t scary or mysterious. It’s understandable, and already in use externally by many people.
Yes, the rfid field is deep, wide, and potentially overwhelming. Books can (and have 
) been written on their uses. But you can get to understand what rfid tech you’re already using (work badges, hotel keys, payment cards, etc) and roughly what they’re capable of. You can look at the possibility of cloning tags, getting something that you can scan and use with your phone, or using it to secure your house, computer, or safe. I’m no expert, but I know enough and have enough toys for it to be a fun hobby, If you then decide to take it to the next step and get an implant, you’re choosing where it goes, what you’re using it for, and what you’re writing on it.
As for what I hope to do someday, work badge and URL on a NExT. (You can also use the NFC side of it to trigger shortcuts on a phone.) Someday, I may get an Apex and enjoy the 2FA features, new file storage implementation, or use it to unlock my imaginary Tesla. If/when a contactless payment-capable solution comes to the US I’ll be considering that, too.
Don’t forget blinkies. I might not get one, but lots of people seem to enjoy having them. The fact that modern phones come with NFC readers mean that you can light up a xSIID anywhere.