Butterfly seems to be taking over everywhere. I recently moved to a new building, and they're using it, as well as every individual apartment having fob-based locks on a separate system, without any key backup. We had our first power outage a few weeks ago, and it meant I had no way of locking my door behind me. The person's described problem at least doesn't apply here, though, since the same fob works on the front door.

Additionally, the staircases were fobbed to get back in, which meant immediately after getting into the staircase, I had no way of getting back onto my floor. They pretty quickly propped all the doors open, at least, but still seems pretty awful from a trade-off perspective as a tenant. I'm sure it makes the management of keys in general a billion times easier for the building, though.