They actually are doing the knock to wake. BLE works and is an instant lock/unlock. Sending a command via wifi will let you know (on the phone) that the lockitron is in a power save mode and the command will be executed in 20 minutes (or whatever the actual time) or when you knock on the door. So if you leave the house and forgot to lock the door, you could lock it remotely and know it'll lock itself eventually. Knocking does work consistently to wake the device up.

It's definitely not the same experience though. I live in a condo and have the lockitron on my unit's door. I have the choice between opening the lockitron app in the elevator and send the unlock signal via wifi, but that means I'll need to knock for sure. Or I could wait until the elevator gets there and try to unlock, and if i'm really lucky it will be via BLE and unlock instantly, but generally the BLE hasn't managed to connect yet and I get no indicator, so I send the command to early and I need to knock anyway.

Speed is such a critical factor here. It doesn't take that long to pull your keys out, and it feels more awkward to stand and wait at your own front door than it does to fumble with the keys for a while. If I'm carrying groceries or a baby, then Lockitron has the potential to make things easier, but currently I still need to fiddle with my phone for a while (maybe in the elevator, but still) and knock so it doesn't really feel easier than using a key.