I’ve long wanted to do this, as a kid I added NFC (at the time, simply RFID) door locking to my 1989 jetta so I didn’t have to fumble for keys. It turns out I do live in the future. I don’t lock my house, so that’s one less key right away, but there are some keyless door locks on the market if you still need them, and those could probably be automated with something like home assistant. I have a tesla that uses a phone for a key. Work has a key card, it’s a proprietary system but I could shrink one into a ring or something. I don’t carry cash, but instead use a magnetic wallet on my phone from popsockets (apple makes one too) for physical cards, although I mostly use apple pay. No digital driver’s license here yet however, so I needed a place to keep cards anyway. In Seoul the metro pass is a simple NFC sticker that you place on the back of your phone. So, no keys for me! Everything is built around the phone, which is fine until I lose access to it…